The traffic slowed down because of the heavy snow in Yushu county, presenting a new __________ to the recovery from the earthquake.
| A．suffering | B．disaster | C．challenge | D．damage |
.Many a student ______ the importance of learning a foreign language.
| A．have realized | B．has realize | C．have been realized | D．has been realized |
.The gas works ______ near the city.
| A．is | B．are | C．were | D．Be |
.The surroundings of his house ______ clean now.
| A．is | B．are | C．was | D．Were |
.The committee ______ over the problem among themselves for two hours.
| A．has argued | B．has been arguing | C．have argued | D．have been arguing |
.The public ______ generous in their contributions to the earthquake victims.
| A．is | B．was | C．are | D．has been |