Question

关于几道sat语法题

1. To persuade his parents to let him study abroad, Kenneth described other students' positive experiences, (explains how foreign study would benefit his future career,and assured) them that he could get financial aid.
括号里应该改为explained how..（后面一样），为什么逗号能连三个动词啊？不是一个句子里只能有一个动词吗?

下面两题问括号里为什么错了，怎么改？
2.Cuban music was so popular in the Colombian city of Cali (thus becoming )the basis for the dance scene that predominated three during the 1940s.
3.In 1988 a Soviet icebreaking ship helped free three gray whales that had become trapped in the Arctic ice after they (had swam) into the coastal waters of Alaska to feed.

Answer 1

1. 这时PARALLEL STRUCTURE,每个逗号之后看为紧连着主干，所以可以用三个或更多的动词。譬如： I can (到此为止是主干） swim, dance, and run. 每个动词的形式要相同。

2. 时态错误，一个句子里面时态要一致，因为句子前面有was... 所以thus becoming要改为thus BECAME.

3. had become... 是过去完成时，那么同上，had swam也应该是过去完成时，但是注意，swam是动词swim的过去式，不是过去分词，过去分词是swum,所以改为 had swum

Answer 2

一个句子里不是只能有一个动词吗，这是复句，所以可做。

thus became

had swum

Answer 3

1.是平行 described explained assured 这三个词引导三个分句 构成平行结构。 （sat 经常考哦！）
2.前半句 是 was所以时态要对应 用became
3.前面是had become 后面是态是对应的 用had 但是 swim-swam-swum 过去完成时 是 had swum