_____ do you write to your parents?—Once a month.[ ]

Do you like your pet dog?-Sure. I think it’s good _____our old people.[ ]

I have a pen . I like very much .

hat do you think of genetically modified food (转基因食品)? —We all think ______ is careless ______ some scientists to say it is safe before doing any experiment.

If you are a little careful, I think you can _____the problem.