弥散性血管内凝血不可缺少的化验有A．血小板计数 B．纤维蛋白原定量 C．凝血酶原时间

用所给动词的适当形式填空。

1. His father stopped ________ (work) because of his illness.

2. Mary often helps her moth _______ (do) the housework after school.

3. Project Hope _______ (train) many teachers so far.

4. He _______ (listen) to music when we called him that evening.

5. We _______ (learn) two thousand English words in the last four years.

6. My old grandfather has come here _______ (take) his bag back.

7. There is a group of children _______ (play) football on the playground.

Many girls are afraid ______ dogs. [ ]

A. at

B. to

C. about

D. of

萃取是利用混合物中各组分在同一溶剂中（）的不同，而使各组分得到分离的操作。

A、溶解度

B、挥发度

C、密度

D、沸点

可行性研究是基本建设前期工作的重要内容，其主要任务是______。

A．对项目的必要性和可行性作分析预测
B．对项目技术的先进性、经济的合理性作论证和比较
C．应该包括A、B两项
D．对项目的必要性和先进性进行论证

冷饮食品加工过程中的最主要的卫生问题是______。