Last night Dad and Mum didn’t come back home ________ I finished my homework.

please pass the key _ _ the lock. —oh! Is it a set _ _ keys?[ ]

_______have you been learning to swim?—Half a year. [ ]

Please welcome Beibei ______ our class.I think she can be our good friend. [ ]

I wonder if youfor a picnic tomorrow. —If it,I will go.