And too many people in a small place make 18 hard to keep thecities safe and clean.And too many people in a small place make 18 hard to keep thecities safe and clean.Yet quiet a lot of people still 19 living in big cities.18.A it B them Cthis Dthat19A suggest Benjoy Cfinish Davoid
问题描述：
And too many people in a small place make 18 hard to keep thecities safe and clean.
And too many people in a small place make 18 hard to keep thecities safe and clean.Yet quiet a lot of people still 19 living in big cities.
18.A it B them Cthis Dthat
19A suggest Benjoy Cfinish Davoid
答
18题选A，19题选B。先理解句意：并且太多人在一个小地方使得保持城市的安全和清洁变得很难。但很多人还是喜欢住在大城市。
18题的it 作形式宾语，替代的是后面的真正的宾语动词不定式。通过Yet 可知，前后两句是转折关系所以19题选enjoy。
（另：句子好像有点错误，make-makes, 句子的主语并不是人，而是一个客观情况，quiet-quite）
答
AB
答
18 A
19 B
it 是形式主语,真正的主语是to keep thecities safe and clean；
enjoy doing 享受；喜欢做某事
答
18A 19B
it 是形式主语，代替的是后面的主语： keep the cities safe and clean