Unhealthy food can do harm to your hair; ____.[ ]

I forgot to bring my pen, would you please lend ________ to me

下列各句中，没有语病的一句是

Did you notice John was not at work today?—No.If _______ working,I would have noticed it.

________ my teacher didn’t tell me directly, I still felt that I didn’t live up to her expectation