Question

—Hey, who’s that man over there? He    us since we came in.  

—The one by the door? I don’t know. He looks like a lawyer or something, not a journalist. Perhaps he      here to look round, like us.

1. A.
   has watched；only came
2. B.
   is watching；had only come
3. C.
   has been watching；has only come
4. D.
   had been watching；came

Answer 1

C
 本题考查时态。since后接从句,谓语动词用一般过去时,主句动词用现在完成时或现在完成进行时。第二个空是描述的预先在有关的境况，故不用一般过去时。