It was difficult to deliver the...

Câu hỏi: It was difficult to deliver the letter_______the sender had written the wrong address on the envelope.

A. though

B.  but

C. so

D. because

A. Could you give me a lift

B.  Would you mind if I smoked

C. What do you plan to do

D. Would you like a cup of tea

A. have been/are built

B.  was/were built

C. was /would be built

D. had been/ were built