since when的意思,用法,例句since when 可以直接用来引导问句吗?还是太多的中国化英语,3Q

since when的意思,用法,例句
since when 可以直接用来引导问句吗?还是太多的中国化英语,3Q

Since when :什么时候开始
可以,例句如下：
1.Since when have you been here?
你从何时起就在这个地方的?
2.Since when has he had a beard?
他从何时开始蓄起了胡子?
3.Since when has he been missing?
他是从什么时候失踪的?