. In our class, when the bell rang and the teacher closed his book, it was a ______for everyone to stand up.
| A．mark | B．chance | C．signal | D．measure |
. The police refused to _____ the clues they were working on.
| A．exhibit | B．disclose | C．expose | D．discern |
. What you have done is _____ the doctor's orders.
| A．attached to | B．resistant to |
| C．responsible to | D．contrary to |
The shop-assistant was straight with his customers. If an article was of _____ quality, he'd tell them so.
| A．minor | B．humble | C．inferior | D．awkward |
. The continuous rain was _____ for the exceptional poor harvest
| A．blamed | B．condemned | C．accused | D．charged |
. The rocks are very big with _____ of colors on them.
| A．bands | B．marks | C．rails | D．shapes |