帮我看几道英语语法题需要正确率Flight 242 is experiencing mechanical difficu

帮我看几道英语语法题需要正确率
Flight 242 is experiencing mechanical difficulties.We predict a delay of less than two hours and ask for your patience.If the plane's air conditioning _______ within two hours,all passengers will be reassigned to other flights.
is not repaired
is repaired
were repaired
will be repaired
If the building _______ according to the correct specifications,it wouldn't have collapsed during the hurricane.
weren't built
had been built
isn't built
hadn't been built
I couldn't finish writing my report yesterday because my computer was completely locked up,but if Larry had been in the office,he _______ it right away.
fixed
would have fixed
wouldn't have fixed
didn't fix
Donna has wanted to be a doctor all her life,but she didn't have the opportunity to attend medical school.She _______ a fine doctor now if she'd studied medicine.
isn't
would be
is
wouldn't be
Some people prefer to continue working for years after retirement age even though they have the resources to retire.Many others would retire early if they _______ the opportunity,but they can't.
have
had
didn't have
had had