___________ certain that his invertion will lead to the development of production.

Remember everybody you meet online is a stranger．So when you can’t see a person, they could be ________．

I feel ____ is your husband who is to blame for the spoiled child.

Tim, don’t touch the box. There is       in it.

—Mary，new copies of Harry Potter are on sale now． —Great! Let’s go and buy       this afternoon．