There is hardly an environment on earth _____ some species of animals or other have not adapted successfully.

Four dollars a pair? I think it′s a bit too much．　— If you buy three pairs, the price for each will ______to $3.5．

His sister left home in 1998，and ________ since

They are ________ little girls _________ they can’t dress themselves.

We can use Wechat（微信） to talk with each other online.—Really Could you please show me how ______it