下列说法正确的是

①水银不是银 ②干冰不是冰 ③铅笔不含铅 ④金刚石不含金[ ]

A.①④

B.②

C.②③

D.①②③④

—May I come in？ I’m sorry I am late.

—Come in, please tell me       .

A、why you are late again       B、what were you doing

C、who did you talk with