?Do you know ________ going to stay in London?

?No, I don't. Maybe a few days.

A. when he is

B. how long he is

C. when is he

D. how long is he

---Do you know ______going to stay in London?

---No, I don’t．Maybe a few days．

1. A.
   when he is
2. B.
   how long he is
3. C.
   when is he
4. D.
   how long is he