With more forests being destroyed, huge quantities of good earth      each year.

Since the time humankind started gardening, we _____to make our environment more beautiful.

Jane _____ these families of chimps for many years and helped people understand how much they behave like humans.

 This is the best chance for you to go abroad. Don't ________. 

—Do you regret having left your first job?—Why should I?I　　　as much,but I enjoy more of it.