几道非谓语的题,希望网友能详解一下为什么.

几道非谓语的题,希望网友能详解一下为什么.
9.In order not to be disturbed,I spent three hours _____ my study.
A.locking B.to lock C.locked D.being locked
15.If law-breaker ____,the society will be in disorder.
A.made unpunished B.came unpunished
C.not punished D.went unpunished
16.He must be angry,for we heard the glass ____ on the floor.
A,being broken B.break C.to be break D.broken
17.You can fly to the UK this morning _____ you don’t mind changing planes in
A.because B.provided C.unless D.so far as
18._____ in this way,the situation doesn’t seem so disappointing.
A.To look B.Looking at C.Looked at D.To be looked at
19._____ in a recent science competition,the three students were awarded
scholarship totaling 21,000 dollars.
A.To be judged the best B.Judged the best
C.Having judged the best D.Judging the best
20.A cool rain was falling,_____ with snow.
A.mixed B.mixing C.to mix D.having mixed
22.The assistant worked late into the night,_____ a long speech for the
president.
A.to have repaired B.repairing
C.repaired D.having repaired
24.The missing singer was last seen _____ the voice close to the bridge.
A.exercising B.to be exercising C.exercise D.to exercise