they have been expecting a splendid crop.that's what they have been___1 waiting 2 waiting for 3 waiting to 4 waiting on请问选择哪一个,及分别说出为什么对与错

问题描述:

they have been expecting a splendid crop.that's what they have been___
1 waiting 2 waiting for 3 waiting to 4 waiting on
请问选择哪一个,及分别说出为什么对与错

2

2
wait 是不及物动词,作“等待”讲,必须和for 连用,所以不选1 (没for),3,4(介词不对)