I was about to swim in the river _________ the guide shouted at me．

1. A.
   when
2. B.
   while
3. C.
   as
4. D.
   during

STRANGERS parties go wild these days. The main idea of them is to never let the people know who their matches are until the last minute. These are some popular practices that are storming the world’s youth on this V-day.

Speed dating

It’s exactly what the name implies. Complete with a timer, a whistle and 50 willing singles, speed dating is not the traditional dinner and a movie type of first date. Singles pay US $35 for three minutes with more than two dozen future dates. They ask questions and try to get to know each other. At the sound of a whistle, they do the same thing all over again―25 times in all.

Lock and key party

Women are given a lock and men are given a key, upon arriving at the party. Each key and lock has several matches. One can hunt for his/her later-to-be sweetheart in various groups, and try out the key or lock. Each time a lock and key match the pair are entered into a ballot (票数） for top prizes!

Dinner in the dark

Waiters wearing night vision glasses guide the guests through the pitch-black dining room. They are seated at the table and familiarized with the wine glass and plate. Food is handled with the fingers. People will not see the food they are eating or the guests at their table until the dessert course. At that moment, dining partners will appear.

Message party

Have A Cocktail, Leave A Message! When you arrive, you get a tag with a number and a pad of post-it notes. If you see someone you like, write a message on the message board. But wait… You’ve got a message… Go and collect it! You can make new friends and win lots of gifts. The more messages you leave on the bulletin board, the more chances you have of winning prizes.

1.What do you think the similarities of these parties are?

   A. All the parties have very strict rules for their members.

   B. If you want to go to any of the parties, you have to buy a ticket.

   C. All the parties are aimed at strangers who want to be lovers.

   D. All the parties are suitable not only for the young but for the old.

2. In which party does a participant have to be careful with the time?

A. Speed dating.                             B. Lock and key party.    

C. Dinner in the dark.                       D. Message party.

3.If you go to the Dinner in the dark, ________.

   A. you have to wear night vision glasses    

   B. you have to eat with your hands

   C. guests eat all the courses in the darkness

   D. your dining partners will help you choose the food

4. How many of the parties offer gifts or prizes?

   A. 1.                  B. 2. C. 3.               D. 4.

When people lose legs after accidents or illnesses, emergency care and artificial limbs（假肢）often allow them to walk again. Newts （蝾螈） in the same situation, on the other hand, can grow limbs back on their own! Scientists have known for a long time that certain animals can re-grow limbs, but they haven’t quite figured out how these creatures do it.
Researchers have now come up with some new ideas. Their work may give people the ability to re-grow lost limbs. The researchers started with two simple experiments：when you cut a newt’s leg at the ankle, only the foot grows back；when you cut off a leg at the very end, the whole leg grows back. In both cases, the re-growth begins with stem cells. Stem cells can develop into nearly any type of cell in the body.
How do a newt’s stem cells know when to grow only a foot and when to re-grow a whole leg?
This question relates to another mystery. In newt’s, a cut-off leg will grow back only if the nerve bundle（神经束）in it also grows back , but if something prevents the nerve bundle from growing, the stem cells at the wound won’t re-grow a new leg.
In its study, a British team focused on a protein called n-AG. When the team prevented nerves in a limb from growing, but added the n-AG protein to stem cells in the limb, the limb still re-grew. That protein seems to guide limb re-growth. People have proteins that are similar to n-AG. Further research into these materials may someday help human limbs recover by themselves.
40. In the experiments, the researchers cut off a newt’s foot or leg to find out _____.
A. what stem cells were                    B. whether they would grow back
C. how long it would take to re-grow    D. how they would re-grow
41. A newt will re-grow its leg if _____.
A. its ankle was cut off but the nerve bundle was good
B. its leg was cut off and the nerve bundle stopped growing
C. its leg was cut off and the nerve bundle could grow back
D. its ankle and the nerve bundle were cut off
42. What do the underlined words “these materials” refer to?
A. Nerve bundles and proteins.         B. Proteins similar to n-AG.
C. Stem cells and proteins.              D. Stem cells and nerve bundles.
43. The first sentence of the passage _____.
A. acts as a lead–in                      B. shows where researchers got their new ideas
C. states the author’s opinion           D. describes the result of researchers’ studies

STRANGERS parties go wild these days. The main idea of them is to never let the people know who their matches are until the last minute. These are some popular practices that are storming the world’s youth on this V-day.

Speed dating

It’s exactly what the name implies. Complete with a timer, a whistle and 50 willing singles, speed dating is not the traditional dinner and a movie type of first date. Singles pay US $35 for three minutes with more than two dozen future dates. They ask questions and try to get to know each other. At the sound of a whistle, they do the same thing all over again―25 times in all.

Lock and key party

Women are given a lock and men are given a key, upon arriving at the party. Each key and lock has several matches. One can hunt for his/her later-to-be sweetheart in various groups, and try out the key or lock. Each time a lock and key match the pair are entered into a ballot (票数） for top prizes!

Dinner in the dark

Waiters wearing night vision glasses guide the guests through the pitch-black dining room. They are seated at the table and familiarized with the wine glass and plate. Food is handled with the fingers. People will not see the food they are eating or the guests at their table until the dessert course. At that moment, dining partners will appear.

Message party

Have A Cocktail, Leave A Message! When you arrive, you get a tag with a number and a pad of post-it notes. If you see someone you like, write a message on the message board. But wait… You’ve got a message… Go and collect it! You can make new friends and win lots of gifts. The more messages you leave on the bulletin board, the more chances you have of winning prizes.

1.What do you think the similarities of these parties are?

   A. All the parties have very strict rules for their members.

   B. If you want to go to any of the parties, you have to buy a ticket.

   C. All the parties are aimed at strangers who want to be lovers.

   D. All the parties are suitable not only for the young but for the old.

2.In which party does a participant have to be careful with the time?

A. Speed dating.                          B. Lock and key party.    

C. Dinner in the dark.                    D. Message party.

3.If you go to the Dinner in the dark, ________.

   A. you have to eat with your hands

   B. you have to wear night vision glasses

   C. guests eat all the courses in the darkness

   D. your dining partners will help you choose the food

4.How many of the parties offer gifts or prizes?

   A. 4.                  B. 3.              C. 2.              D. 1.