问题
选择题
I hate travelling by air_______ you usually have to wait for hours before the plane takes off.
A．because
B．though
C．until
D．Unless
答案
答案：A
题目分析：句意：我讨厌乘坐飞机旅行，因为通常在飞机起飞之前需要等好几个小时。A因为 B虽然 C直到D除非;根据题意，前面是结果，后面是原因，所以要用because。故选A.