题目

（3分）如图所示、在倾角为的斜面上以速度v。水平抛出一小球，该斜面足够长，则从抛出开始计时，经过时间为              小球落到斜面上。 答案： — Why did the teacher ________ the exercise was ver-y important? — He thought it was one of the parts we should master． [　　] A．suggest B．propose C．suppose D．insist