求英语大神帮忙介词填空~·~

1.I will try and get the report to you before you go __ leave, so you can work on it before you come back.2.He is envious __ his friends because they could afford such fine houses.3.There'll be plenty of activities to participate __ when you get there.4.They set __ and started to climb the mountain as the sun was rising.5.People who work in heavy industry are subjected __ the noise of machines.6.__ first sight, the woman appeared to be very old, but she actually wasn't.7.Snow run-off accounts __ the regular spring floods in the area.8.My introduction  __smoking came at an age when most people start to think about giving it up.9.I saw him put on his jacket, pick __ his case, and go out.10.He never met them, but communicated ___ them through email.