问题
选择题
现将10gA和足量B混合加热，A和B发生化学反应，10gA完全反应后生成8gC和4gD，则参加反应的A和B的质量比是（ ）
A．1：1
B．2：1
C．4：1
D．5：1
答案
10gA完全反应后生成8gC和4gD，由质量守恒定律可知，参加反应的B的质量为2g，故参加反应的A和B的质量比是10g：2g=5：1．
故选D．
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现将10gA和足量B混合加热，A和B发生化学反应，10gA完全反应后生成8gC和4gD，则参加反应的A和B的质量比是（ ）
A．1：1
B．2：1
C．4：1
D．5：1
10gA完全反应后生成8gC和4gD，由质量守恒定律可知，参加反应的B的质量为2g，故参加反应的A和B的质量比是10g：2g=5：1．
故选D．
| 任务型阅读。请认真阅读下列短文，并根据所读内容在文章后表格中的空格里填入一个最恰当的单词。 注意：每个空格只填1个单词。 | ||||||||||
| Communication Principles How you see yourself can make a great difference in how you communicate. "Every individual exists in a continually changing world of experience of which he (or she) is the center". Many communication scholars and social scientists believe that people are products of how others treat them and of the messages others send them. But every day we experience the centrality of our selves in communication. A student, for instance, may describe a conflict with a teacher as unfair treatment:"I know my teacher doesn't like the fact that I don't agree with his opinions and that's why he gave me such a poor grade in that class. "The teacher might say the opposite. Each person may believe that he is correct and that the other person's view is wrong. The concept of self originates in communication. Through verbal and nonverbal symbols, a child learns to accept roles in response to the expectations of others. You establish self-image. The sort of person you believe you are, by how others think of you. Positive, negative, and neutral messages that you receive from others all play a role in determining who you are. Communication itself is probably best understood as a dialogue process. Our understanding of communication comes from our interactions with other people. In a more obvious way, communication involves others in the sense that a competent communicator considers what the other person needs and expects when selecting messages to share. So,the communication begins with the self, as defined largely by others,and involves others, as defined largely by the self. Communication occurs almost every minute of your life. If you are not communicating with yourself (thinking, planning, reacting to the world around you), you are observing others and drawing inferences from their behavior. Even if the other person did not intend a message for you, you gather observations and draw specific conclusions. A person yawns and you believe that person is bored with your message. A second person looks away from you and you conclude that person is not listening to you. A third person smiles (perhaps because of a memory of a joke he heard recently) and you believe that he is attracted to you. We are continually picking up meanings from others' behaviors and we are constantly providing behaviors that have communicative value for them. More often than not, you may have hurt someone accidentally and you may have tried to explain that you did not mean that. You may have told the other person that you were sorry for your statement. You may have made a joke out of your rude statement. Nonetheless, your comment remains both in the mind of the other person and in your own mind. You cannot go back in time and erase your messages to others. Communication cannot be reversed (倒退),n or can it be repeated. When you tried to re-create the atmosphere, the conversation,and the setting, nothing seemed right. Your second experience with a similar setting and person made far different results. | ||||||||||
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