分布式数据库系统不具有的特点是________。A．分布式 B．数据冗余 C．数据分

阅读理解。

     A story tells that a senior villager led some other villagers carrying salt day and night to a town in order to

trade rice as food the winter. One night they camped in a wilderness with a starry sky above. The senior

villager, obeying the tradition passed down from forefathers, took out three blocks of salt and threw them into

the campfire, probably to predict the changes of weather in the mountains.

     All eagerly waited for the old man's" weather report":if the salt in the fire produced crackling sound, they

would have good weather in store；if no sound was produced, it then meant the good weather would soon end

and a storm would come at any moment.

     The senior villager looked serious. The salt in the campfire made no sound at all. Convinced by this bad

sign, he urged (催促) the whole team to set out immediately after daybreak. A young man in the group,

however, insisted that they should not start in such a hurry, considering it superstitious to" forecast weather by

using salt.

     It was not until the next afternoon that the young man caught up on the wisdom of the old man when the

weather suddenly changed, with cold winds blowing and a snowstorm raging. In fact, the method used by the

clan head could be well explained by modem science:whether or not salt produces sound in campfire depends

on air humidity (湿度).That is to say, when a storm approaches, due to high humidity, the dampened salt

blocks will not produce any sound in fire.

1.The senior villager predicted the changes of the weather _____ while camping in a wilderness that night.

A. by taking out salt

B. by burning salt in fire

C. in a superstitious way

D. depending on his wisdom

2. "The weather report" they got that night _____.

A. had a bad sign

B. gave wrong information

C. was superstitious at that time

D. was scientific according to modem science

3. After reading the passage, we can know _____.

A. the lower humidity is, the bigger sound salt will produce in fire

B.the higher humidity is, the bigger sound salt will produce in fire

C. dampened salt blocks will result in winds and storms

D. the young man never wanted to understand the old man

4. From the passage, it can be concluded that _____.

A. old people are always right

B. old people are wiser than the young

C. young people shouldn't regard old ideas as useless or out of date sometimes

D. young people usually have different opinions from the old

—What did he say just now?  

—He wondered___________________.

A．when would the film begin

B．how he could get to the zoo

C．if he could join us or not

D．where he will go tomorrow

化学毒物损伤的防护原则的主要措施不包括（）

A、器材防护

B、工事防护

C、中毒防护

D、服用预防药

斗式提升机的检修内容主要是斗链、链条和保险销的更换。

铝电解质的物理化学性质包括哪些指标？