Maria has _____ trouble _____ math, so she often asks her math teacher for help.
—I wonder_______ you’ll water this kind of tree. —Once a week.
We can have_______ bluer sky if we create________ less polluted world.
—Do you know if Cindy wilt drive to Italy this weekend?—Cindy? Never! She___ driving.
I can________ be a nurse.I’m not a very patient person.
The earthquake which happened in Yushu________ 14th April 2010 was a big disaster.