________ some teenagers don’t realize is ________ difficult life can be after they get
addicted to drugs.
| A．That, how | B．That, what |
C．Wh at, what a |
D．What, how |
Whenever I get into trouble, I always _______ Peter.
| A．carry on | B．count on |
| C．turn on | D．move on |
At minus 130℃, a living cell can be _________ for a thousand year.
| A．spared | B．protected |
| C．preserved | D．developed |
Earth is believed ______ by an object the size of Mars at some point in the distant past before itssurface cooled.
| A．to be hit | B．to have hit |
| C．to have been hit | D．to hit |
our earth, or else it will be no longer fit for us to live on.
| A．Protected | B．To protect |
| C．Protecting | D．Protect |
With temperature ______ so rapidly, we could not go with the experiment.
| A．fall | B．falling |
| C．fallen | D．to fall |