问题补充:
Now most families have only one child our country’s one-child policy.
A. since B. because C. because of
答案:
解析:since由于,自从……以来;because因为;because of因为。句意:因为我国的一孩政策,现在许多家庭只有一个孩子。Because和because of都表示原因,区别是前者接从句,后者接名词性短语。下文our country’s one-child policy为名词性短语,故选C.