—Oh, doctor, The wound on my leg is infected. —You really shouldn’t have left it _______ to the sun.
. This is really a big problem for all of us, but I’m sure we can ________ it soon.
Mike has recently caught A-H1N1. ________, he will have to be away from school for several days.
The best way to explore _______ countryside is on _______foot.
. As we watched the panda, we stood still, ______ to one another.
___the clouds, you would find the airplane in the sky easily