( )Even the top students in our class can't work out this problem. So it _____ be very difficult.
| A．may | B．must | C．can | D．need |
( )This machine is very easy to use.______ can learn to use it in a very short time.
| A．Somebody | B．Anybody | C．Nobody | D．Few people |
( ) One of his friends ______ his daughter sometimes.
| A．visiting | B．is visiting | C．visitor | D．visits |
( )The game is _____ funny that many of them like it.
| A．such | B．so | C．very | D．quite |
( )Are there _____ trees behind the house?
| A．a | B．the | C．much | D．any |