Hurry up! We’ll be late for the plane.— Don’t worry. The plane won’t_______ until two hours later.

We usually use “an” before a word beginning_____ a vowel (元音音素).[ ]

Why are you late, Jim?—Because there _________ a lot of traffic when I came here.

You always spend only a little time on your study. You really ____me down.— I’m sorry, Mum. I won’t do that again.

________of the students in our class are from the north.