环境中某些化学物质被生物体吸收后不断积聚、浓缩。这种现象称为A．生物吸收 B．生物放

下图为我国区域示意图。A为水库，是B城市的唯一水源，C处为山地。读图回答问题。

（1）应采取什么措施来保护B城市的水源？

_________________________________________________________________________。

（2）某企业拟在C处山坡上开辟采石场，指出其可能对该处造成的生态破坏。

_________________________________________________________________________。

把10千克糖溶解在200千克水里，糖和糖水的重量比是（　　） A．1：20 B．1：21 C．1：19

语法填空

     It was a winter morning, just before Christmas, while most people were warming up their cars, my

husband, Trevor, had to ride his bike 4 kilometers away from home to work. On his 1. ________(arrive), he parked his bike outside the back door 2. ________usual. After 10 hours of labor, he returned to find

his bike gone, 3. ________was our only transport. Trevor used it to get to work, and also the bike was

used 4. ________(get) groceries, saving us from having to walk long distances from 5. ________we live.

     I was so sad that I wrote to the newspaper and told 6. ________our story. Shortly after that, several

people in our area offered to help. One wonderful stranger even bought a bike, and then called my

husband to fetch it. Once again my husband had a way to get to and 7. ________his job. It really is

8. ________honor that a complete stranger would go out of their way for someone they have never met

before.

     People say that a smile can 9. ________(pass) from one person to another, but acts of kindness from

strangers are even more so. This experience has had a spreading effect in our lives because it

10. ________(strong) our faith in humanity. And it has influenced us to be more mindful of ways we,

too, can share with others.

前端收费指投资者在申购基金时缴纳申购费用，其费率是按( )划分的。

A．持有时间
B．持有份额
C．投资份额
D．投资金额

配制电解液时应将（）慢慢往水里加入。

A.硝酸

B.盐酸

C.硫酸

D.醋酸