5.Few people have _________(探索) the area from St.Louis to the Pacific. 6.He ________(反应) angrily to the news that he would retire. 7.There are no simple __________(解决方法) to the problem of overpopulation. 8.Traffic ___________(交通阻塞)has become more and more common. 9.It is not __________(方便的) for me to come now;I am busy. 10.The government has to _________(提供) against a possible oil shortage in the coming months.

explored

reacted

solutions

congestion

convenient

provide