这句话怎么没有用and的连接?

这句话本身就有问题- -.
第一,在这句话中subject 是people.但是后面又来了个 they.一个句子只能有一个主语,所以是run-on sentence.改的话可以改成
1.
From early 1980s 'when' people were gradually released from restrictive and stubborn
ideas,they started to get out of China to learn new things,accept
controversial Phenomena .
我在这儿把前面一部分弄成了一个dependent clause
2.
'and' 也行
From early 1980s people were gradually released from restrictive and stubborn
ideas and they started to get out of China to learn new things,accept
controversial Phenomena .
这个改发虽然纠正了语法错误,但是syntax上还是 不是很顺.
第二,to learn new things,accept controversial Phenomena .这句话也是需要 and.一般如果就是两件事/东西的话都不用 ‘,’ 的,直接 a and b.三件事以上才用 a,b,and c.（但是也需要 and来连接）
总之不加 and 是不行的
好累~