In recent years,operations (become) much safer than they (be) in the past.

分类: 作业答案 • 2022-01-09 18:05:57

问题描述：

In recent years,operations __ (become) much safer than they __(be) in the past.
用括号内单词正确时态填空,

答

have became was

In recent years,operations __ (become) much safer than they __(be) in the past.