After my husband died, my world crashed around me. My six children were 10, nine, eight, six, three and 18 months, and I was overwhelmed with the responsibilities of earning a living, caring for the children and simply keeping my head above water.
I was fortunate to find a wonderful housekeeper to care for the children during the week, but from Friday nights to Monday mornings, the children and I were alone, and frankly I was uneasy. Every unusual noise or any late-night phone call filled me with fear. I felt incredibly alone.
One Friday evening I came home from work to find a big beautiful German shepherd(牧羊犬) on our doorstep. It was obvious he wanted to make the house his home. The children took an instant liking to "German" and begged me to let him in. I agreed to let him sleep in the basement until the next day. That night I slept peacefully for the first time in many weeks.
The following morning we made phone calls and checked lost-and-found ads for German’s owner, but with no results. Saturday night he was still with us. 
On Sunday I had planned to take the children on a picnic. Since I thought it best to leave German behind in case his owner came by, we drove off without him. When we stopped to get gas at a local station, we were amazed to see German racing to the gas station after us. He stayed again Sunday night.  
Monday morning I let him out for a run while the children got ready for school. He didn’t come back. We thought we’d never see him again. On Friday evening, German was back again. We took him in, and again he stayed until Monday morning, when our housekeeper arrived. It went like this for almost 10 months. We looked forward to his coming each Monday morning he left home.
Each week, between German's visits, I grew a little braver, but every weekend I enjoyed his company. Then one Monday morning we patted his head and let him out for what turned out to be the last time. He never came back. 
【小题1】What does the underlined part in the first paragraph mean?

Antifreeze is a liquid(液体) that is added to water to keep it from freezing． When water freezes and turns to ice，it expands(膨胀)．The force of water expanding is so great that it will break the hardest metal．Water is used in car engines(发动机) to keep them cool while they run，and if this water is allowed to freeze in winter it can break the iron block of the engine．That is why antifreeze is necessary．
Water freezes at 0℃；the usual kind of antifreeze will not freeze until the temperature is－40℃．A mixture(混合物) of five parts of water and four parts of antifreeze will prevent freezing at－18℃；four parts of water and five parts of antifreeze reduce this to －22℃．
Alcohol is a kind of good antifreeze，but when the air is running it becomes hot and the alcohol boils away，so it must be changed very often．Most people use antifreeze that does not boil away when the engine is running．There are several chemicals that do this．One of the most popular is called ethylene glycol．
【小题1】people use ________ to keep car engines cool．

The human body is a living machine, and, like all machines, it needs “fuel” to supply it with energy. This is provided by the food we eat. But how much do we need to stay healthy?

The energy value of food is usually measured in calories(卡). A calorie is the amount of heat required to raise the temperature of 1 kg of water by 1℃. The number of calories people need per day is different, as the picture shows. Also, the number of calories you use at any one moment normally depends on the activity you are in. For example, you need more calories for standing than for sitting, more for running than for walking, and so on.

The energy in food is in the form of three kinds of chemical materials—carbohydrate（碳水化合物）, protein（蛋白质） and fat. Carbohydrate provides 3.8 Cal /gm of the energy, protein 4.0 Cal/gm, and fat 8.8 Cal/gm. Each food contains different amounts of these materials, as the round pictures show.

(P= protein      C= carbohydrate    F=fat)

1.How many calories are needed to raise the temperature of 5kg of water from 35℃ to 90℃?

2.Which of the following contains the most amount of calories?

3.Who needs the most amount of calories each day?

4.Which of following is True?　　

5.This passage mainly tells us ______.