21.你骗不了我.
I'm from Missouri.
22.见机行事
Play to the score.
23.肯定有人唆使他去干那件事.
There must be someone who had put him up tothat.(正式:唆使=instigate)
24.他不是不愿意帮助你,而是他心有余而力不足.
It's not that he doesn't like to help, but that the spirit iswilling,but the flesh is week.