—Did you know ______ just now?
—Their plane didn't take off on time because of the thick fog.
A.what did they happen | B.what happened to them |
C.what they happened | D.what they have happened |
—Did you know ______ just now?
—Their plane didn't take off on time because of the thick fog.
A.what did they happen | B.what happened to them |
C.what they happened | D.what they have happened |