David,turn off the TV ___ no one is watching it.

David,turn off the TV ___ no one is watching it.
But it ____ off already!The music is from the radio.
A so that,has been turned B when ,has turned
C if ,has been turned D because ,has turned
可是为啥 if后面接的是is watching 而不是watches
为什么是 has been turned 而不是 has turned

选C的翻译为：大卫,如果现在没人看电视,就关了吧?大卫说：但是电视已经关了啊,音乐是收音机里的.
再问： 为什么 if后面接的是is watching 而不是watches
再答： if后面也可以加现在进行时，因为watch可以表示一个持续的动作，其实语法没有那么太严格，而且这里用watches也可以。另外，排除法也可以，先排除B和D，然后A的意思不通。

回答的不错