如图所示，电路中所有元件完好，但光照射到光电管上，灵敏电流计中没有电流通过，其原

下列关于控制哮喘发作药物的描述中，正确的有()。

A．同时吸入短效β₂激动剂与糖皮质激素时，应先吸入后者

B．需喷人两剂沙丁胺醇时，两次之间至少间隔3～5分钟

C．糖皮质激素作为长期抗炎治疗目前推荐的首选给药途径为吸入

D．严重哮喘发作者应尽早大剂量静脉给予糖皮质激素，症状缓解后逐渐改为口服和吸入维持

E．抗胆碱能药物与β₂激动剂联合使用适用于夜间哮喘多痰者

Let children learn to judge their own work. A child learning to talk does not learn by being corrected all the time :if corrected too much, he will stop talking. He notices a thousand times a day the difference between the language he uses and the language those

Around him use. Bit by bit .he makes the necessary changes to make his language like other people's. In the same way, children learn to do all the other things: they should learn to do without being taught, such as to walk, run, climb,  whistle, ride a bicycle—compare their own performances with those of more skilled people, and slowly make the needed changes. But in school we never give a child a chance to find out his mistakes and correct them for himself. We do it all for him. We act as if we thought that he would never notice a mistake unless it was pointed out to him, or correct it unless he was made to .Let him work out, with the help of other children if he wants it, what this word says, what the  answer is to that problem, whether this is a good way of saying or doing this or not.

If it is a matter of right answer, as it may be in mathematics or science, give him the answer book. Let him correct his own papers. Why should we teachers waste time on such routine（常规）work? Our job should be to help the child when he tells us that he can’t find the way to get the right answer .Let the children learn what all educated persons must some day learn ,how to measure their own understanding, how to know what they   know or do not know.

小题1:According to the passage ,the best way for children to learn things is by______

A．listening to skilled people's advice

B．asking older people many questions.

C．making mistakes and having them corrected

D．doing what other people do小题2:which of the following does the writer think teachers should NOT do?

A．Give children correct answers.

B．Allow children to make mistakes.

C．Point out children's mistakes to them.

D．Let children mark their own work.小题3:According to the writer, teachers in school should______

A．allow children to learn from each other

B．point out children's mistakes whenever found

C．correct children's mistakes as soon as possible

D．give children more book knowledge小题4:The passage suggests that learning to speak and learning to ride a bicycle are ____

A．different from learning other skills

B．the same as learning other skills

C．more important than other skills

D．not really important skills

对评估实施步骤审定时，要求评估实施过程的重要步骤经过周密计划和安排。

由外界提供丙烯和乙烯开丙烯制冷机和乙烯制冷机是乙烯装置开车的优化条件，而不是必备条件。