Once air pollution in most cities, it is hard .
Before a problem can be solved, it must be obvious ______ the problem itself is. A. what B that C which D why
It is the most instructive lecture that ________since I came to this school. A attended B had attended C am attending D have attended
Do you wake up every morningenergetic and ready day? A feel B to feel C feeling D fell
No one ________ be compared with Yao Ming in playing basketball. A can B need C must D. might
In 1492, Columbus_______ on one of the Bahama Islands, but he mistook it for an island of India. A lands B landedC has landed D had landed