What’s your first impression ________ Mrs Wang?—-She looks serious. I think she’ll be strict _____ us _______her own work.

Another drug that has helped improve people’s health is penicillin, _________ is _________ by many _________ one of the most important medicines.

Do you know the girl ____ red?-Oh, she is my sister.[ ]

Please repeat this sentence______. [ ]

Is this ____ cap? –No, it’s not ____.