单选题
Addition of any chemical compound to the environment in quantities ______ a significant fraction of the total content of gasoline may have unexpected environmental consequences.
A、
that constitute
B、
which constitutes
C、
that are substituted by
D、
which substitute
【正确答案】
A
【答案解析】
[注释]语法结构要求时态统一，故选[A]。
提交答案
关闭