Scientists have created GM tomatoes which ______ fresh for 45 days, three times as long as normal to

题目简介

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

题型：单选题难度：中档来源：不详

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。