Scientists ______ thousands of chemicals before they decided on the right one in

题干

Scientists ______ thousands of chemicals before they decided on the right one in the end.

A．tried out	B．found out
C．worked out	D．turned out

上一题下一题 0.64难度单项选择更新时间:2012-04-10 04:53:31

小学学科试题库

初中学科试题库

高中学科试题库