7、动词

When problems such as energy crisis, pollution and population explosion _____, people are asked to share the bitterness and endure the hardship.

A. are arisen B. arise

C. arising D. arisen

【正确答案】B

【高考考点】考查动词。

【详细解析】从题干可知when引导的时间状语从句中缺少谓语动词，故排除C、D两项;arise“出现、发生”，是不及物动词，无被动语态。故正确答案为B。