胃底腺与幽门腺的最主要区别是（）

A.腺的位置

B.腺的形态

C.腺的疏密

D.腺细胞的组成

E.腺的大小

– ______ you didn’t turn up at the party last weekend?

-- My plane was delayed by two hours.

A．What was it

B．When was it

C．How long was it that

D．Why was it that