【单选题】将纯水 放入抽空、密闭的石英容器中,不断加热容器,可以观察到哪种现象 ( )
【单选题】( )指生产者用户根据所购产品的技术说明书,需要量、交货时间、退货条件、担保书等内容与供应商签订最后的订单。
【单选题】Why does the professor say this:
A.
To emphasize the negativity of the public's reaction to a certain theory.
B.
To complain about the behavior. of the scientific community.
C.
To introduce a reason for a shift in scientific opinion.
D.
To ask the students their opinion of a theory he described.
【简答题】乙烷的优势构象为 ,丁烷四种典型构象分别是 、 、 、 ;优势构象是 。
【单选题】盛有水的敞口杯子放置在实验台上是否有安全隐患?
【单选题】Why does the professor say this:
A.
To emphasize the importance of commercials
B.
To correct something that he said earlier
C.
To identify the time limits for most commercials
D.
To relate new information to a previous example
【简答题】将 CaCO 3 (s) 、 (s) 和 CO 2 (g) 以任意比例混合,放入一密闭容器中,恒温下建立化学平衡,则系统的组分数 C =______ ;自由度 ¦ =________ 。
【单选题】Why does the student go to the professor's office?
A.
To change his schedule
【单选题】Why does the professor say this:
A.
To remind the students of the topic for today's session
B.
To indicate that he expects the students to read the textbook
C.
To encourage the students to participate in the discussion
D.
To demonstrate his respect for the students in his class
【单选题】Why does the man go to see his professor?
A.
He is worried about the professor's class.
B.
He wants to bring up the grade in her class.
C.
He would like some advice about his classes.
D.
He needs to get the woman's signature.