What has made you so happy，Mary?-Oh，I’ve just________an old friend I haven’t seen for years.[ ]

Though tigers are ______ to people, they are ______ now and we should protect them or they will die out.

We didn’t know anything about the fox _____ the teacher told us.

Haven’t I told you that you should get home earlier—Yes, but I __________ home earlier than I usually do.

My mother is ill. I have to take care of her at home.