开车过程中，为了缩短启动时间，反充液氧，最佳时机是（）。 A.向塔内送气两小时 B.
题型：单项选择题
问题：
开车过程中，为了缩短启动时间，反充液氧，最佳时机是（）。
A.向塔内送气两小时
B.两台膨胀机全开达到正常
C.主冷见液后开始积液时
D.氮气纯度90%以上时
题型：单项选择题
As everyone knows, classroom teaching is one of the most important ways that the students learn English. In English classroom teaching, teachers have to arouse the students’ interest so that they may learn better. There are many ways to arouse the students ‘interest; body language is an effective way in English teaching practice.
Nowadays, with the reform of English teaching methods, more and more English teachers organize their teaching process in English. That means teachers have to instruct and explain basically in English, and the students also should use English in class contemporarily. However, the students can’t speak English very well. Besides, their vocabulary is limited and their expressive ability is not good enough, either. These limitations have made it difficult to realize the communicative English in class. According to the students’ present level and practical situation, body language is required. For example, if a teacher gives an instruction “You two, please come to the blackboard”, the students can easily understand it if the teacher looks at or points to some two students. Then, the teacher points to the blackboard. The students will carry out the order without obstacles even if they don’t hear the key word “blackboard” clearly.
In the actual English teaching, teachers frequently use body language to improve both the teaching effect and the students’ characters. In school education, body language plays a positive role in building students ‘characters. This is because teachers are usually respected and what the teachers say and do will be possibly imitated by the students. In a word, teachers’ graceful body language helps to improve students’ artistic appreciation and their characters, especially their morality. If students develop wonderful body language, they will surely have a smooth relation with each other. Teachers reflect their affection of body language on the students not only by setting a good example, but also build a bridge between teachers and students. As a matter of fact, teachers’ friendly appearance can greatly encourage students to study enthusiastically. Body language not only motivates students’ interest but also improves the effect of classroom teaching greatly.
As we know, learning English needs practice. The 45 minutes in class is very precious and should be valued, during which the students should practice as much as possible. To make good use of the limited time, teachers should adopt some effective methods. The use of body language cannot only make the students listen more attentively in class, but can also deepen their impression and imagination. Teachers usually have to explain some language points, and at this time, they can also carry out their teaching task easily with the help of body language in the teaching process.