问题
选择题
Some green beans, ______ long enough, can be poisonous (有毒的).
A．if not be cooked
B．if not cooked
C．if not cooking
D．if not being cooked
答案
答案：B
题目分析：句意：一些绿豆如果煮的时间不够久.可能会有毒。这里是表条件,而且是被动语态,相当于：Some green beans,if they are not cooked long enough, can be poisonous (有毒的). 当主从句的主语一致的时候，可以省略从句的主语和be动词，所以是B。