根据个人所得税法律制度的规定，下列各项中，以取得的收入全额为应纳税所得额计征个人所得税的有（）。

Marketing is important;______, we're hiring a new public relations firm.

A．therefore

B．even though

C．nevertheless

D．but

An important result of Vespuccis voyage was______.

A．confirmation of a new continent

B．Vespucci" s naming of "America"

C．improved relations between the U.S. and Germany

D．the discovery that the earth is round

We learn from the text that amateur astronomers______.

A．began their discovery earlier than the professionals

B．tend to be the leaders in the area of astronomy

C．have some advantages in discovering new comets

D．established some theories on how comets come into being

Galileo made an important discovery at the age of

A．True

B．False

Little did they realize that they ______ (make) an important discovery in science.

Important () his discovery might be, it was regarded as a matter of no account in his time.

A. when

B. until

C. as

D.although

From this passage, we can infer that the author

A．holds that it is impossible to predict an earthquake.

B．is very surprised about this discovery.

C．thinks that scientists could do better.

D．thinks this discovery is very important for earthquake prediction.

He is regarded by all as a genius,______the important discovery was made.

A．who

B．whom

C．about whom

D．by whom

From this article, we may draw the conclusion that

A．The focus on the bird is an important yet missing characteristic, and without it even the successful discovery will seem hollow

B．It is not the bird but the human efforts that attract a lot of readers' attention

C．The article argues that the book is with great content and great focus

D．Although the book is not stylish, readers still find interesting things in its characterization and extended history of the bird

This discovery of the New World is ______ to the Italian navigator Christopher Columbus.

A．indebted

B．contributed

C．owned

D．attributable