SC's Question number - 741 , 742

741). The energy source on Voyager 2 is not a nuclear reactor, in which atoms are actively broken apart; rather a kind of nuclear battery that uses natural radioactive decay to produce power.

(A) apart; rather

(B) apart, but rather

(C) apart, but rather that of

(D) apart, but that of

(E) apart; it is that of


742). The evolution of the technology of microelectronics over the past decade has been so rapid that it is sometimes called a revolution.

(A) has been so rapid that it is sometimes

(B) has been rapid enough sometimes to be

(C) has been rapid enough it is sometimes

(D) is so rapid it has sometimes been

(E) is so rapid that it is sometimes

Answers:

741). (OG 10th Ques no - 172) - OA - B

OE: Choice B, the best answer, follows an idiomatic form of expression for paired coordinates--not X, but rather Y; here rather is optional but preferable because it helps establish a contrast between the two types of energy source.

A - incorrect - incorrectly uses a semicolon rather than a coordinating conjunction (but) to connect the coordinate parts; a semicolon should be used to join independent clauses (http://gmat-grammar.blogspot.com/search/label/Semicolon)

C, D, E - incorrect - that of has no grammatical referent and thus produces illogical and incorrect sentences

742). OA - A - idiomatic - ..so X that Y..

B, C - incorrect - awkward - ....rapid enough ...sometimes..to be

D, E - incorrect - wrong tense