问题
选择题
— It's sunny today. How about going skiing in Ying Yue Park?
— ______! Let's ask the twins to go with us. [ ]
A. Sounds great
B. Best wishes
C. Good luck
D. That's OK
答案
答案：A
搜题请搜索小程序“爱下问搜题”
— It's sunny today. How about going skiing in Ying Yue Park?
— ______! Let's ask the twins to go with us. [ ]
A. Sounds great
B. Best wishes
C. Good luck
D. That's OK
答案：A
微观示意图有助于我们认识化学物质和理解化学反应．
甲是一种比较清洁的燃料，已知甲和乙能在一定条件下反应生成丙和丁．
| 物质 | 氢原子碳原子氧原子 甲 | 乙 | 丙 | 丁 |
|
| 微观 示意图 |
|
|
|
|
（2）甲中碳、氢、氧元素的质量比为______．
（3）在化学反应前后，可能变化的是______（填序号）．
a．原子种类 b．原子数目
c．分子数目 d．元素种类
（4）该反应中，乙和丁的质量比为______．
