题目内容
【题目】— It's been five years __________ we met last time.
— Yes. What a long time!
A. whenB. untilC. sinceD. while
【答案】C
【解析】
句意：---我们上次见面已经五年了。----是的。好久没见了！考查连词。A. when当…时候，既可表示时间段也可表示时间点，一般情况下，从句时态是一般过去时，主句使用过去进行时；B. until直到，主从句时态一般一致；C. since自从…以来，表示一般时间，后面一般跟过去的时间点或一般过去时的从句，主句使用现在完成时；D. while当…时候，表示时间段，while后面的从句一般使用过去进行时。结合句意可知填since；选C。
【题目】 I would like to talk to you about space vegetables, and to show you that space vegetables are healthy and good for you.
Space vegetables are grown from seeds (种子) that have been taken to and brought back from outer space. The seeds are affected by radiation (辐射) and low gravity in outer space. When they are brought back to the Earth, these seeds produce vegetables that are bigger, healthier and more nutritious (有营养的) than normal vegetables. However, some people worry about eating space vegetables. They think that space vegetables might not be good for us and could give us cancer as a result of their exposure (暴露) to radiation in space. People should not be scared, as space vegetables are actually perfectly healthy.
Here are some facts that you should know about space vegetables:
Space vegetables are grown from seeds that are carefully selected (选择). When seeds are brought back from space, people test the seeds to make sure that the vegetables they grow will be safe to eat. There are no traces of radiation after testing.
Space vegetables are better for you than normal vegetables. For example, space tomatoes stay fresh for twenty days, which is one week longer than normal tomatoes. Another popular space vegetable is the pepper (辣椒). Space peppers contain 20 percent more Vitamin C than normal peppers.
After genetically modified (基因改进的) foods come onto the market, people worry that they are eating unknown things. For example, if nut genes are put inside potatoes, people allergic (对…过敏) to nuts might get very sick from eating these potatoes because they do not know they are also eating nuts. Unlike genetically modified foods, space vegetables have not been genetically changed. This means that no new genes are put into the vegetables, so they won't be harmful to your health.
Space vegetables | |
Space vegetables are healthy, good and safe for you to eat. | |
【1】taken to ensure the quality of spacevegetables. | Before being taken to the outer space, the seeds are carefully selected. |
When being brought back from space, seeds are tested to see 【2】 there are traces of radiation which might lead to cancer. The testing has proved that they are perfectly healthy. | |
Advantages of space vegetables | After being affected by the radiation and low gravity in outer space, the seeds 【3】 into bigger and healthier vegetables. For example, space peppers contain more Vitamin C. |
Space tomatoes can be 【4】much longer than normal tomatoes． | |
There is no 【5】 of eating something because none of the genes is changed. | |