问题
选择题
. The flowers his friend gave him will die unless __________ every day.
A. watered B. watering
B. water D. to water
答案
答案：A
A。因“花”与“浇水”之间为被动关系，所以选过去分词。其实，unless watered可视为unless they are watered之省略。类似的还有：Unless changed. this law will make life difficult for farmers. 这项法令除非进行修改，否则将给农民的生活造成困难。