If you sleep less than seven hours, you are three times more to catch a cold.
He placed one of the arrows __ his bow.
___ from a plane, the Great Wall looks like a huge dragon.
Africa is actually connected with Asia at the spot ___ the Suez Canel was dug.
Many buildings ___ in the eathquake.
Some weak bridge may not ___ in an earthquake. A,stay up B. fall down C. fell down D. fell off