Sentence Correction
试题详情
题目：
Most vaccines are derived from weakened or killed strains of the same virus that they prevent, unlike the derivation of smallpox vaccine from a different virus altogether.
选项:
A、(A) the derivation of smallpox vaccine from a different virus altogether
B、(B) smallpox vaccine, which is derived from a different virus altogether
C、(C) smallpox's vaccine, which gets derived from a different virus altogether
D、(D) when smallpox vaccine is derived from an altogether different virus
E、(E) the altogether different virus from which smallpox vaccine is derived
答案:
B
