My new neighbor is a _____ person; he never speaks to anyone and nobody knows where he is from and what he is doing.

If it is __________ for you to go out tonight, would you like to go to the cinema with me?

I’m sure that if you make good use of your ______ time, your English will be improved in a short time.

The children were warned of not being too_________about things they are not supposed to  know.

Our     resources and fine policy can certainly provide foreigners with the advantages of     developing their business.