We may put the flowers in the classroom. (改为被动语态)
The flowers may ______ ______ in the classroom.

单项选择题According to the passage, collecting antique clocks ______.

单项选择题What were the demonstrators protesting about

单项选择题When there are black block clouds in the sky, ______.

单项选择题Ⅱ. 完形填空 Close 通过下面短文，掌握其大意，然后再各题所给的四个选项(A、B、C和D)中选出一个最佳选项。

单项选择题The two farmers ______ on that day.