It worried her a bit
网友回答
填thatthat her hair was turning gray才是真正主语
It只是形式主语
她的头发已经开始慢慢变白,这使她有些担心.
======以下答案可供参考======
供参考答案1:
填 that供参考答案2:
thatthat her hair was turning gray做真正主语
供参考答案3:
填that it作形式主语 真正主语是that引导的从句
如果填表示因为的单词，此句的意思就翻译不通
供参考答案4:
that！！！！！
供参考答案5:
because
forsince只要是因为的意思都可以
供参考答案6:
so that