51._______ from the outer space， our earth looks like a water-covered ball.
A. Having seen B. Seeing C. Seen D. Having been seen
52.I don‘t mind _______ the decision as long as it is not too late.
A. you to delay making B. your delaying making C. your delaying to make D. you delay to make
53.The picture _______ on the wall is painted by my nephew.
A. having hung B. hanging C. hangs D. being hung
54._______ such heavy pollution already， it may now be too late to clean up the river.
A. Having suffered B. Suffering C. To suffer D. Suffered
55.They pretended to be working hard all night with their lights _______.
A. burn B. burnt C. burning D. to burn
参考答案：
51.正确答案：C答案解析：根据分词结构的逻辑主语分析，选项A、B、D都不能和主句中的主语构成逻辑的主谓一致的关系。只有选项C是正确答案。
52.正确答案：B答案解析：这是一个带有逻辑主语的动名词结构。依据前面所讲，逻辑主语应是一个带有形容词性的物主代词，其后的动词delay也应该是一个动名词。
53.正确答案：B答案解析：本题考查现在分词作定语的用法。根据句意“墙上挂的那幅画是我侄子画的”，可知空白处所填的动词形式在句中作定语，解题关键在于分析picture与hang之间的逻辑关系。
54.正确答案：A答案解析：本题考查分词短语作状语的用法。分词作状语，其逻辑主语必须是句子的主语，而本句的主语看似是it，其实它为形式主语，真正的主语为不定式，而不定式省略了逻辑主语for people，所以应用现在分词，又因already，应用完成时。
55.正确答案：C答案解析：burn“点燃、发亮、发光”，是不及物动词，所以和their lights是主动关系，所以用现在分词。
