英语语法上的问题 有3道题不懂,谁能教我一下.

英语语法上的问题 有3道题不懂,谁能教我一下.
1.I wondered_______to come to the party.
A.if he is asked B.if he should have been asked
2.The children_______many times not to go near the lake.
A.have been told B.were being told
3.The goods _______when we arrived at the airport.
A.were just being unloaded B.were just been unloaded
最好能说明一下原因 thanks a lot!