下列LD和LED叙述，正确的是（）A.LD和LED都存在谐振腔，且能量在_爱下问搜题

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问题单项选择题

下列LD和LED叙述，正确的是（）

A.LD和LED都存在谐振腔，且能量在其产生

B.LD存在阀值电流，而LED没有

C.LD和LED的发出功率都与注入电流成正比

答案

参考答案：B

完形填空

According to legend, a young man while wandering the desert came across a spring of delicious crystal-clear water. The water was so sweet, he   21  his leather container so he could bring some   22  to a tribal elder who had been his teacher.
After a four-day journey he   23  the water to the old man who took a deep drink,   24  warmly and thanked his student lavishly for the sweet water. The young man returned to his village with a happy   25 .
Later, the teacher let another student   26  the water. He spat it   27 , saying it was awful. It   28  had been no longer fresh and   29  unpleasant to drink because of the old leather container.
The student challenged his teacher: “Master, the water was smelly. Why did you   30  to like it?”
The teacher replied, “You only tasted the water. I tasted the   31 . The water was simply the container for an act of loving-kindness and nothing could be   32 .”
I think we understand this lesson best when we receive   33  gifts of love from young children.   34  it’s a tray or a bracelet, the   35  and proper response is   36  and expressed thankfulness because we love the idea within the gift.
Gratitude doesn’t always come naturally.   37 , most children and many adults value only the thing given   38  the feeling embodied in it. We should remind ourselves and   39  our children about the beauty and purity of feelings and expressions of gratitude.   40 , gifts from the heart are really gifts of the heart.

C．nevertheless

D．meaningless

C．imagination

D．appreciation

A．Unfortunately

B．rather than

C．better than

填空题

明以后，“官话”是以（）为基础语言、以（）为标准音、以（）为其语法楷模的市民社会语言。