mails yesterday.Normally, I my e-mail-box for days.

If my friends have any problems, my door is ______ open to them.

Grandpa has changed a lot.- So he has. He spends more time than he used to ______ gameswith the children.

Everything is full of yellow dust because of the sandstorm（沙尘暴）.！

________ the weather is very changeable these days, many people have caught a cold.