托福考试

【单选题】 An atom is a basic structural unit of matter, the smallest particle of an element （） into chemical combination. 
A. that can enter 
B. can it enter 
C. when entering it can 
D. that enters can 

【单选题】 Why does the author mention "a crow" in line 12
A．( to indicate the size of Archaeopteryx
B．( To specify the age of the Archaeopteryx fossils
C．( To explain the evolutionary history of Archaeopteryx
D．( To demonstrate the superiority of the theropod to Archaeopteryx

【单选题】 Acoustics, (the) study of sounds, (is) one of the (oldest) of the (physically) sciences.
A．the
B．is
C．oldest
D．physically

【单选题】 Transistors (exhibit) a high amplification factor, operate without (distorted) over a (wide frequency) range, and can be made (extremely small).
A．exhibit
B．distorted
C．frequency
D．extremely small

【单选题】 Why are marine organisms good candidates for fossilization
A．they have more fleshy structures than land organisms
B．It is likely that they will be buried rapidly
C．The water environment speeds the decay caused by bacteria
D．it takes longer for them to be preserved