单项选择
12. Light _______ faster than sound . A. was traveling B. is traveling C. travel D. travels
D 陈述自然现象,用一般现在时.主语是单数,用三单形式,谓语动词+S
这是事实,用一般现在时,选D
答:ttomissinordernottodosth详情>>
答:B 被动语态,be found to do. A中的made与found均为过去分词,冲突!详情>>
问:hArd work 和hArd--working有什么区别
答:一个是名词 一个是形容词撒详情>>