3. Not one of the potential investors is expected to make an offer to buy First Interstate Bank until a merger agreement is signed that includes a provision for penalties if the deal were not to be concluded.
- is expected to make an offer to buy First Interstate Bank until a merger agreement is signed that includes a provision for penalties if the deal were
- is expected to make an offer for buying First Interstate Bank until they sign a merger agreement including a provision for penalties if the deal was
- is expected to make an offer to buy First Interstate Bank until a merger agreement be signed by them with a provision for penalties if the deal were
- are expected to make an offer for buying First Interstate Bank until it signs a merger agreement with a provision for penalties included if the deal was
- are expected to be making an offer to buy First Interstate Bank until they sign a merger agreement including a provision for penalties if the deal were
Answer: C
请教本题的语法点，c项的be signed 为什么用动词原形be?
