21.Ice is less [denser] [than] the liquid [from which] [it] is formed.
　　答对率：50%
　　答案：a

　　22.James Baldwin s plays and short stories,[which are] to [some degree] autobiographical,established [them] as a [leading] figure in the United States civil rights movement.
　　答对率：43%
　　答案：c

　　23.Thunder can be [listened] from a [maximum] distance of about ten miles [except] under [unusual] atmospheric conditions.
　　答对率：35%
　　答案：a

　　24.The quantum theory states……,such as light, is given off and absorbed in tiny definite units called quanta or photons.

　　A.energy that
　　B.that it is energy
　　C.it is energy
　　D.that energy
　　答对率：50%
　　答案：d

　　25.Geysers are round near rivers and lakes, where water drains through the soil……

　　A.surface below the deep
　　B.deep below the surface
　　C.the deep below surface
　　D.the deep surface below
　　答对率：50%
　　答案：b

　　26.Although [he is] employed in the scientific and [technical] fields,the metric [system] is not generally [utilized] in the United States.
　　答对率：46%
　　答案：a

　　27.[Beneath] the deep oceans that [cover] two-thirds of the Earth, intriguing [secret] of the planet are [concealed].
　　答对率：43%
　　答案：c

　　28.The pioneer John Chapman [received] the nickname "johnny Appleseed" because he [planted] apple seedlings during [him travels] in [what] are now Ohio, Indiana, and Illinois.
　　答对率：50%
　　答案：c

　　29.On March 1,1867,……to the Union when President Andrew Johnson s veto was overridden.

　　A.since the state of Nebraska had been admitted
　　B.admitted that the state of Mebraska
　　C.the admission of the state of Nebraska
　　D.the state of Nebraska was admitted
　　答对率：50%
　　答案：d

　　30.The best known of all the Arctic birds,……

　　A.birdwatchers favor ptarmigans
　　B.being ptarmigans and birdwatchers favorites
　　C.favored by both ptarmigans and birdwatchers
　　D.ptarmigans are a favorite of birdwatchers
　　答对率：47%
　　答案：d