阅读理解
People who talk and sing to plants are not crazy, according to Mr. Braymar, an agriculture expert(农业专家). "In
fact, singing and talking to plants makes them grow better," says Braymar. The reason is quite simple -- when we
sing or talk to plants, we breathe out carbon dioxide (二氧化碳) which plants need to live and grow. Plants take in
the carbon dioxide during the sunlight hours and produce oxygen(氧气) which people need to live. Singing and
talking is effective, however, only during the daytime.
1. Plants need ________ in the daytime.
A. carbon
B. dioxide
C. carbon dioxide
D. oxygen
2. Carbon dioxide helps plants ________.
A. to take in oxygen
B. to sleep well
C. to drink water
D. to live and grow better
3. The point of the paragraph is that singing and talking to plants can be ________.
A. good for the people who do so
B. helpful to both people and plants
C. dangerous to people D. polluting the air
b Z(g)。反应达到平衡后，测得X的转化率为25%。而且，在同温同压下还测得反应前混合气体的密度是反应后混合气体密度的5/6，则a和b的数值可能是( B)