[单项选择]Not until an infant hedgehog opens its eyes ______ its nest to follow its mother about.
A. it leaves
B. and leaves
C. leaving
D. does it leave

[单项选择]Not until an infant hedgehog opens its eyes ______ its nest to follow its mother about.
A. it leaves
B. and leaves
C. leaving
D. does it leave

[单项选择]A firm should continue adding to its capital until the marginal product of capital is:（）
A. equal to the marginal revenue product of labor.
B. greater than the cost of capital.
C. equal to the cost of capital.

[单项选择]In the author's eyes, FASEB might prove its influence if it ______.
A. campaigned for a big sum of money for the companies
B. enabled academic community to be more respected
C. extended its success into other spheres
D. competed for attention with some rivals

[单项选择]The coronary sinus opens into （）.
A. right atrium
B. superior vena cava
C. inferior vena cava
D. right ventricle
E. left atrium

[单项选择]The article opens and closes with descriptions of two news reports, each ______ one major pointing contrast with the other.
A. makes
B. made
C. is to make
D. making

[单项选择]The Children Restaurant opens______.

[单项选择]Not until many years later
A. the whole truth became known
B. did the whole truth become known
C. the whole truth has become known
D. has the truth become known

[单项选择]

The book opens with a broad survey, in part Ⅰ , of the historical literature on technical change. It attempts to provide a guide to a wide range of writings that illuminate technological change as a historical phenomenon. The first chapter discusses aspects of the conceptualization of technological change and then goes on to consider what the literature has had to say on (1) the rate of technological change, (2) the forces influencing its direction, (3) the speed with which new technologies have diffused, and (4) the impact of technological change on the growth in productivity. A separate chapter is devoted to Marx. Marx’s intellectual impact has been so pervasive as to rank him as a major social force in history as well as an armchair interpreter of history. Part Ⅱ is, in important respects, the core of the book. Each of its chapters advances an argument about some significant characteristics of industrial technologies. Chapter 3 explores a variety of less visible forms in
A. Chapter Ⅰ
B. Chapter Ⅱ
C. Chapter Ⅲ
D. Chapter Ⅳ

[单项选择]When she opens her mouth, the fox ______.