Of the two brothers, Bill is ________ younger one, and he is a quiet boy, ________ that most adults like very much.
| A．a; one | B．a; the one |
| C．the; one | D．the; the one |
__________ that these creatures are linked to a common ancestor.
| A．As is believed | B．What is believed |
| C．That is believed | D．It is believed |
These viruses, if ________ in, can result in illness or even death.
| A．breathing | B．breathed | C．breathe | D．to breathe |
Please take down my telephone number ________ something important happens.
| A．in case | B．now that | C．even though | D．as if |
Mountain climbing ________ be very tiring, and many people feel sick ________ the atmosphere gets thinner.
| A．may; while | B．can; as | C．must; though | D．should; for |
It is generally considered unwise to give children ________ they wants.
| A．however | B．no matter how | C．whatever | D．no matter what |