题目

 不管以何种比例混合，只要总质量一定，充分燃烧后生成的二氧化碳的量不变的是    A．乙烯（C2H4）和苯（C6H6）        B．乙醇和丙醇（CH3CH2CH2OH）    C．乙醇和乙醚（C2H5OC2H5）         D．甲醛（ HCHO）和乙酸                         答案：D完形填空 　　We have a big playground in our school. We all like to __(1)___ games __(2)___ after school. 　　It's Friday. We have only two classes __(3)___ the afternoon. When school is __(4)___, a lot of students go to the playground. Look! The boys of Grade Two are __(5)___ a basketball match. Some girls are __(6)___ and shouting. Football is our favorite sport. Many teachers are also __(7)___ football. 　　Li Ming, Li Lei and Wei Fang are students of Grade One. They are __(8)___ a frisby. They are playing very __(9)___. It's half past five now. It's time __(10)__ home. The students all leave the playground. (1) A．do B．make C．play (2) A．there B．have C．at there (3) A．on B．in C．at (4) A．beinning B．finish C．over (5) A．having B．making C．playing (6) A．seeing B．looking C．watching (7) A．playing B．playing the C．play (8) A．putting B．dropping C．throwing (9) A．good B．nice C．well (10) A．for B．to go C．go