C. when; beginning D. which; began

【答案】A

【解析】

【详解】考查定语从句和时态。句意：阿司匹林的第一次试验发生在1899年，当时霍夫曼供职的公司开始将这种粉末形式的药物分发给医生，供病人使用。此处1899是先行词，在后面的非限制性定语从句中作时间状语，所以第一个空填when；根据in 1899，可知后面的非限制为性定语从句用一般过去时态，所以第二空填began。故选A。

2.Studies show that kids living and studying in a harmonious environment are less likely to become .

A. abnormal B. aggressive

C. alarmed D. opposed

【答案】B

【解析】

【详解】考查形容词。A. abnormal反常的；B. aggressive好斗的，有进取心的；C. alarmed受惊的； D. opposed对立的。句意：研究表明，生活和学习在和谐环境中的孩子不太可能变得好斗。结合句意可知答案为B。

3.One of the good points of the Internet is that we can people with similar intetests in distant areas and comminute with them.

A. correspond with B. bring up

C. link up D. call on

【答案】A

【解析】

【详解】考查词组。A. correspond with一致； B. bring up提出，教育； C. link up连接； D. call on访问，拜访。句意：互联网的优点之一是我们可以与在遥远地区有相似兴趣的人通信和交流。结合句意可知答案为A。

4.If penicillin available, many people from sickness or even small wounds in World WarⅡ.

A. was not; would die B. were not; would have died

C. had not been; would died D. had not been; would have died

【答案】D