A number of tests have been conducted to ______

试题详情及答案解析

A number of tests have been conducted to _______ that these drugs have no side effects.

A．find out	B．look for
C．make sure	D．work out

答案：C

试题分析：考查动词短语辨析。A发现，查明；B寻找；C确保；D制定出，锻炼；句意：为了确保这些药物没有副作用，进行了很多的测试。根据句意说明C正确。
考点：考查动词短语辨析