垄断导致市场失灵的原因包括（）。

The majority of jazz artists in Dr Miller's study were men.

A．Y

B．N

C．NG

In whale bunters' eyes, whales' numbers can be adjusted by__________

A. people's growing awareness of the balance between ecology and business

B. their theory which has been derived from life experiences

C. a flexible biological system in which all species survive

D. the change of balance between market need and the amount of whales

From the last paragraph, we know that______.

A．some artists' paintings were beautiful, so they were masterpieces

B．only art experts could judge they were masterpieces or not, though ugly

C．the artists mentioned above were not really art masters.

D．some of them were art masters, while others were not.

Who were the first watercolor artists？

A．Early cave dwellers.

B．Italian fresco artists.

C．Flemish masters.

D．Eighteenth-century English artists.

Who were the first watercolor artists？

A．Early cave dwellers.

B．Italian fresco artists.

C．Flemish masters.

D．Eighteenth-century English artists.

It can be inferred from the last paragraph that______.

A．very few artists can be good businessmen

B．Watkins"s works were recognized when he was alive

C．it was difficult to preserve the glass negatives

D．photography does harm to one"s eyesight

The author's description of Cro-Magnon paintings mentions which of the following？

A．Some are not very good.

B．It is unusual to see such paintings.

C．Many were drawn by children.

D．The artists were mostly right-hande

Who were the first watercolor artists？

A．Early cave dwellers.

B．Italian fresco artists.

C．Flemish masters.

D．Eighteenth-century English artists.

Who were the first watercolor artists？

A．Early cave dwellers.

B．Italian fresco artists.

C．Flemish masters.

D．Eighteenth-century English artists.