1. 表示时间

4) Inaugurated a second time on March 4, 1901, ______focused on domestic rather than oreign policies.

[A] William McKinley's new term looked forward to and

[B] the new term looked forward to William McKinley and

[C] looking forward to a new term was William McKinley

[D] William McKinley looked forward to a new term

解析：D为正确答案。这句话前半句的-ed分词相当于一个时间状语从句“When he was inaugurated a second time …”，主句的主语应当是人，所以A和D为可能选项，但A中的look forward to后应跟名词，那么只有D为正确选项。

2. 表示条件

5) ________under a microscope, a fresh snowflake has a delicate six pointed shape.[A] Seen

[B] Sees

[C] Seeing

[D] To see

解析：A为正确答案。本句的意思是“在显微镜下看，雪花……”，显然这里的看是“被观察”之义。B、C、D都表示主动，A为正确选项。