As the Internet is expanding day by day, the opportunities for crime ______ as well.
| A．has been | B．is | C．have been | D．are |
Everyone likes to develop a close relationship ______ we trust each other.
| A．which | B．that | C．where | D．when |
Jack decided to risk looking for a place to stay where he arrived, rather than booking ______.
| A．in advance | B．in return | C．in fact | D．in addition |
Low-cost books in paper covers make ______ some of the world’s best literature to readers.
| A．ordinary | B．available | C．comfortable | D．necessary |
He must be helping the old man to water the flowers, ______?
| A．is he | B．isn’t he | C．must he | D．mustn’t he |
—Can I pay the bill by check?
—Sorry, Madam, but it is our managing rule that payment ______ be made in cash.
| A．shall | B．may | C．will | D．can |