—Has John arrived at the hotel?

—Not yet. He       here      a couple of days.

A．is；in

B．will be；with

C．was；before

D．will be；in

申请电讯检疫的船舶首先向卫生检疫机关申请卫生检查，合格者发给卫生证书，该证书，自签发之日起( )个月内可以申请电讯检疫。

A．6

B．12

C．18

D．9