1.He---the black jacket for a blue one.2.Why do the leaves o

1.He exchange the black jacket for a blue one
exchange = 交换 exchange sth.for sth.
2.Why do the leaves on trees change colour in the autumn?
change = 改变
3.Most importantly,you must keep a record of everything you do
Most extremely好像不通,没这种用法,可以说In most extreme situation(在最危急的环境下); Most importantly = 最重要的是