题目内容
果实指数小于1的果实为长圆形。
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采果过迟会增加树体对养分的消耗。
Amplifiers are necessary in many types of electronic equipment such as radios, oscilloscopes and record players. Often it is a large alternating current that has to be amplified.
A junction transistor in the common-emitter mode can act as a resistance amplifier.
The small alternating voltage is applied to the base-emitter circuit and causes large changes of base current which produce small changes in the collector current flowing through the load.
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