-I can’t go with you today. There will be a test tomorrow.

- ______. Maybe next time.

A．It doesn't matter

B．My pleasure

C．I don’t think so

D．You are welcome

一份粉尘样品分散度测定结果如下：其中呼吸性粉尘占（）

A.35%

B.45%

C.15%

D.80%

E.95%