There seems to be two causes as I try to figure out __________ that prevents so many children from being as happy as before.
Hurry up!The train ______. You know it ______ at 8:30 am.
In recent days ,with the help of our teacher , I have made ___ great progress in _____mathematics.
Mrs. Green always helps her mother even though going to work _________most of her day.
We have to admit that the biggest___________ facing the ecosystem is limited resources and the worsening environment.
Your task will be to examine the___________ of constructing a new factory in the United Kingdom.