Look at the mess the boys made! You _______ have taught them how to behave themselves.
| A．must | B．may | C．can | D．should |
In the lab, keeping things clean and organized can help provide a safer ________.
| A． |
system |
B． |
method |
C． |
investment |
D． |
environment |
Nowadays many people travel across China ________ high-speed trains.
| A． |
on behalf of |
B． |
by means of |
| C． |
at cost of |
D． |
in terms of |
In the spring, a season ________ we are 1earning new rhythms of life ， many of us find comfort in the natural world.
| A． |
when |
B． |
where |
C． |
what |
D． |
which |
It's a good idea to choose a(n) ________ destination in case your first-choice tourist spot is not available.
| A． |
annual |
B． |
exact |
C． |
alternative |
D． |
pleasant |
The police searched the area for several days. ________, they found the piece of evidence they were looking for.
| A． |
Generally |
B． |
Originally |
| C． |
Eventually |
D． |
Unfortunately |