28.

32.

32.刘老师会在每次考试前提醒学生好好复习，根据桑代克的基本规律，这是（ ）的体现。

18.He has made another wonderful discovery, ______ of great importance to science.

16.Today, these methods are viewed as practices that can cause harm and are in the last -_______ only to be used when measures have failed and safety is at sever risk.

36.

37.

30.

51. Which of the following is true according to the passage?

17.Hydrogen is one of the most important elements in the universe _______ it provides the building blocks from which the other elements are produced.

9.Mary is looking for some ________ to go with her black and white evening gown for the party.

50. The foremost reason why the egg-based method is defective lies in ________