我国居民的膳食结构属于______。 A．动植物食物平衡的膳食结构 B．以植物性食

阅读理解。

                                                                           Letter A

Dear Mary,

      I like your programmes very much. I'm now writing to ask you something about American social

customs (社交习惯): My American friend wants me to join them in their dinner party. I am very happy

and have decided to go, but I'm a little worried about it, too. The social customs in my country are very

different from here, so I'm afraid of making mistakes.

     Should I bring a present, such as sweet or flowers? Should I arrive on time or a little late? At the dinner

table, how can I know which fork (叉子) or knife to use? How can I let the family know that I'm thankful

for their kindness

                                                                                                                                Wang Lin

                                                                            Letter B

Dear Wang Lin,

      It's a good idea to bring a small present when you go to a dinner party. Flowers are always nice, or you

may bring a bottle of wine (葡萄酒) if you know that your friends drink it.

     You should arrive on time or five to ten minutes late. Don't get there early. If you're going to be more than

fifteen minutes late, you should call and tell them.

     Try to be free at the dinner table. If you don't know about choosing the right fork or knife, just watch the

other people, and follow them. If you still have no idea of what to do ask the person next to you.

     If you like the food, say so. Of course, you'll thank them for the meal and for their kindness. It's also a

good idea to send a thank-you card the day after.

                                                                                                                                               Mary

1. Mary is possibly _______.

A. a good housewife

B. a TV hostess (主持人)

C. a member of the dinner party

D. a friend of Wang Lin's

2. When you go to a dinner party, you'd better not take _______ with you.

A. some wine

B. some flowers

C. some presents

D. some food

3. If you're asked to a dinner party but not sure about what to bring as a present, it's good to bring _______.

A. some fruits

B. a bottle of wine

C. some flowers

D. a knife and fork

4. Which of the following is NOT proper (适当的) for joining in a dinner party?

A. Get there 15 minutes earlier.

B. Make yourself at home.

C. Follow others to use forks and knives.

D. Thank your friends for the meal.

合金工具钢是指用于制造各种（ ）、（ ）用钢的总合

科学实验往往需要设置重复组，其数字结果应当取各重复组的最小值。[ ]

工业革命首先开始于 （   ）。

A．英国

B．美国

C．法国

D．意大利

糊料塑性是怎样影响压型产品质量的？