In many cases, salespeople serve two masters: the seller and the buyer, that’s becuase （）.

A . positive B . possible C . previous D . private

A . not under command B . restricted in her ability to manoeuvre C . restrained by her draught D . underway

A . 这个案例中，腹侧与前面高度相等。 B . 中间和里面是一样的。 C . 外面和中部要保持一致。 D . 腹部和前部在这里是同一个意思。

A .  It is effective only in partition pruning. B .  It is effective only in partitionwise joins provided that the query predicates are different from the partitioning key. C .  It is effective in both partition pruning as well as partitionwise joins provided that the query predicates are identical to the partitioning key. D .  It is effective in both partition pruning as well as partitionwise joins irrespective of whether the query predicates are different from or identical to the partitioning key.

A . with B . by C . on D . i

A . not under command B . restricted in her ability C . restrained by her draught D . underway

A . Every three minutes. B . When a log switch occurs. C . When forces by an administrator. D . When a tablespace is taken offline normal. E . When the redo buffer is one-third full.

A．A medical emergency. B．Police action. C．Traveling. D．All of the above.

A．If it has no ventilation systems. B．If it has a childcare facility. C．If it has no designated areas. D．If it is close to public areas.

A．do B．win C．gain D．receive

A.successful big company． B.successful small company． C.successfuI smalI businesses．

A．impossible B． possible C． sensible D． practical

Sufficient buoyancy （浮力）to support the wearer should be retained by the life preserver after 48 hours in the water, and it should be reliable even after long period of storage.Thus it should be made of materials resistant to sunlight, gasoline, and oils, and it should be not easily set on fire.The position in which the life preserver will support a person who jumps or falls into the water is most important, as is its tendency to turn the wearer in the water from a face-down position to an upright or slightly backward position, with his face clear of the water, even when the wearer is exhausted or unconscious. The method of adjustment to the body should be simple, and self-evident to uninitiated persons even in the dark under the confused conditions, which follow a disaster.Thus, the life preserver should be reversible that it is nearly impossible to get it on wrong.Catches, straps, and ties should be kept to a minimum.In addition, the life preserver must be adjustable to the wide variety of shapes and sizes of wearers, since this greatly affects the position of floating and the self-righting qualities.A suitable life preserver should also be comfortable to wear at all times, in and out of the water, not so heavy as to encourage to take it off on shipboard while the ship is in danger, nor so burdensome that it hinders a person in the water while trying to swim. 1.The passage is mainly about（）. A.the uses of life preservers B.the design of life preservers C.the materials for life preservers D.the buoyancy of life preservers 2.According to the passage, a life preserver should be first of all （）. A.adjustableB.comfortableC.self-evidentD.self-righting 3.United States Coast Guard does NOT require the life preserver to be made （）. A.with as few strings as possible B.capable of being worn on both sides C.according to each wearer's size D.comfortable and light to wear 4.By “the uninitiated individual” （Para）1, Line.4.the author refers to the person （）. A.who has not been instructed how to use a life preserver B.who has a little experience in using a life preserver C.who uses a life preserver without permission D.who becomes nervous before a disaster 5.What would happen if a person were supported by the life preserver in a wrong position？ A.The waves would move him backwards. B.The water would choke him. C.He would immediately sink to the bottom. D.He would be exhausted or unconscious.

A．假使 B．万一 C．在这种情况下

A．①② B．③④ C．①⑤ D．②⑥