[求助]就是不懂WHY?

就是不懂!个位大侠帮帮忙!
LUXIN SC LOOSE-LEAF MATERIALS
26.A growing awareness of the systemic causes of malnutrition {have led many organizations to shifting their emphasis from relief efforts to attempting reforms of} the agricultural and social patterns that contribute to famines.
(A) have led many organizations to shifting their emphasis from relief efforts to attempting reforms of
(B) led many organizations to shifting their emphasis from relief efforts to attempting reforms of
(C) has led many organizations to shift their emphasis from relief efforts to attempts to reform
(D) lead many organizations to shift so as to emphasize not relief efforts but reforms of
(E) leads many organizations to a shifting of their emphasis from efforts at relief to attempts at reforms of
A):C       [Part E COMPLEMENTATION]

27The Product Liability Act would prohibit {a victim of defective products to recover money from the manufacturer unless they can prove} that the manufacturer knew the product was defective.
(A)a victim of defective products to recover money from the manufacturer unless they can prove
(B)that a victim of defective products should recover money from the manufacturer unless he or she can prove
(C)the victim of a defective product from recovering money from the manufacturer unless he or she can prove
(D)victims of defective products from the recovery of money from a manufacturer unless it can be proved
(E)victims of defective products that they shall recover money from the manufacturers unless it can be proved
A):C       [Part E COMPLEMENTATION]

28.It may be another fifteen years before spacecraft from Earth {again venture to Mars, a planet now known to be} cold, dry, and probably lifeless.
(A)again venture to Mars, a planet now known to be
(B)venture to Mars again, a planet now known for being
(C)will venture to Mars again, a planet now known as being
(D)venture again to Mars, a planet that is known now to be
(E)will again venture to Mars, a planet now known as being
A):A       [Part E COMPLEMENTATION]

31.Although the Supreme Court ruled as long ago as 1880 that Blacks could not be excluded outright from jury service, nearly a century of case-by-case adjudication {has been necessary to develop and enforce the principle that all Juries must be} drawn from “a fair cross section of the community.”
(A) has been necessary to develop and enforce the principle that all Juries must be
(B) was necessary for developing and enforcing the principle of all juries being
(C) was to be necessary in developing and enforcing the principle of all juries to be
(D) is necessary to develop and enforce the principle that all juries must be
(E) will be necessary for developing and enforcing the principle that all juries being
A):A       [Part E COMPLEMENTATION]

36.Psychics and astrologers are to the post-modern 1990s {just like an enlightened monk and guru was} to an earlier time.
(A) just like an enlightened monk and guru was
(B) as have been an enlightened monk and guru
(C) what enlightened monks and gurus were
(D) what enlightened monks and gurus are
(E) just the same as enlightened monks and gurus had been
A):C          [TEST 1 SEC.3]