Scientists have created GM tomatoes which fresh for 45 days, three times as long as normal tomatoes.
A. are stayed
B. have been stayed
C. stay
D. stayed
网友回答
A. are stayed
B. have been stayed
(答案→)C. stay
D. stayed
解析： 考查时态。which引导的定语从句是说明转基因西红柿的一般性质，故用一般现在时；又因为stay是连系动词，故选C。