. It’s very kind ______ you ______ say so.

Dear, you should some money for your birthday.— OK. I won’t let a coin go to waste.

The scientists have made an exhaustive study of the virus _______ many people have been inflected.

Have you known MrWang for a long time? — Yes, since he _____ to our school.

Only when you have obtained enough data ________ come to a sound conclusion.