a. act as a buffer, so that it absorbs
b. act like a buffer so as to absorb
c. act as a buffer, absorbing
d. acting as a buffer, absorbing
e. acting like a buffer, absorb
Parallelism + Idiom
The last part of the sentence describes the breakwater and should consist of two grammatically parallel phrases, absorbing ... and protecting, in order to show two equal functions. Act is followed by like to mean to behave or comport oneself and describes the action of a person: He acted like a fool. Here, act as describes the function of a thing; the breakwater ... acts as a buffer. As an inanimate object, a breakwater cannot "behave" itself; it must be performing some function.
90. The peaks of a mountain range, acting like rocks in a streambed, produce ripples in the air flowing over them; the resulting flow pattern, with crests and troughs that remain stationary although the air that forms them is moving rapidly, are known as "standing waves."
(A) crests and troughs that remain stationary although the air that forms them is moving rapidly, are
(B) crests and troughs that remain stationary although they are formed by rapidly moving air, are
(C) crests and troughs that remain stationary although the air that forms them is moving rapidly, is
(D) stationary crests and troughs although the air
that forms them is moving rapidly, are
(E) stationary crests and troughs although they are formed by rapidly moving air, is
