3个a连乘，可以用（ ）表示；3a是表示（ ）连乘。
a3；a个3
– Excuse me, could you tell me ________ for Hong Kong?
– The day after tomorrow.
A. when did you leave
B. when you are leaving
C. where you are going
-20号柴油指（）。
A.凝固点为-20℃
B.燃点为20℃
C.凝固点不高于-20℃
D.燃点不高于-20℃
