问题补充：
Over the past twenty years, American country music become 1.
more and more popular. Some writers are no longer writing about 2.
modern values of the USA. In 1950s, American music was about other3.
things . Money was also thought to be important. Ten years late, 4.
some writers turned other subjects. During these years, many young 5.
students were angry with society. So songs were often full of angry. 6.
Political leaders were not well thought and those songs often made 7.
fun of them. Country music today remains much the same as ago. 8.
One subject which country music often returns is “the good old days”.9.
And in “the good old days”, people love life on the open air. 10.1. become 前面加has
答案：
(答案→)1. become 前面加has
解析：
1. 此句用现在完成时。
2. 正确
3. in the 1950s 在二十世纪五十年代。
4. ten years later，十年以后
5. turn to 转向……
6. 此句用名词。
7. think well of sb 认为某人好，为固定词组，变被动语态of不能丢掉。
8.“从前”，这里用before比较合适
9. return to为固定词组，此句为to提前的定语从句。
10.in the open air 在户外。
