When the man came in, gun in hand, we all stood there, ________．
A．astonished B．astonishing
C．being astonished D．having astonished
If nature does not provide man with the necessary material, it is the laboratory ____ he will turn to for it．
A．where B．that C．which D．what
By the time you have completed the essential training, you _____ exposed to virtually every new feature of the course．
A．are B．will have been C．have been D．will be
_______ more to be pitied than blamed．
A．Uneducated are B．Uneducated is
C．The uneducated are D．The uneducated is
Earth is believed ______ by an object the size of Mars at some point in the distant past
before its surface cooled．
A．to be hit B．to have hit C．to have been hit D．to hit
With temperature ______ so rapidly, we could not go with the experiment．
A．fall B．falling C．fallen D．to fall
