完形填空中定语从句的时态做过许多完型题,下面两个句子给我弄糊涂了：The teacher asked the stude

完形填空中定语从句的时态
做过许多完型题,下面两个句子给我弄糊涂了：
The teacher asked the students to write about the waterfall they ( ) before and one student's paper was just one sentence.
A.visited B.had visited(选A)
After the judge heard what ( ) to them,he said to the businessman.
A.happened B.had happened（选B）
第一题中我看到before便选了B,J结果错了；第二题中我吸取上题经验选A,又错了.
但我总觉得俩题选哪个都行,这是怎么回事?
第一句是个定语从句啊......