Which choice completes the text so that it conforms to the conventions of Standard English?

Question

Ada Lovelace's 1843 notes on Charles Babbage's proposed Analytical Engine, which contain what many historians regard as the first published computer ____ describe operations that no machine then in existence could actually carry out.

Accepted Answer

D. algorithm,. The subject of the sentence is 'Ada Lovelace's 1843 notes on Charles Babbage's proposed Analytical Engine,' and the main verb is 'describe.' The 'which' clause is a nonrestrictive supplement interrupting subject and verb, so it must be enclosed by a pair of commas; the opening comma appears before 'which,' so a closing comma is required after 'algorithm.' (A) A semicolon must join two independent clauses; here it would sever the subject from its verb, leaving two fragments. (B) Omitting punctuation leaves the supplement with only one of the two required commas, so the interrupting clause runs directly into the main verb. (C) A colon must follow a grammatically complete clause; the words before the blank form only a long subject phrase, and the colon would additionally cut the subject off from 'describe.'

Answer

A. algorithm; — A semicolon needs an independent clause on each side; here it would split the subject 'Ada Lovelace's 1843 notes...' from its verb 'describe,' leaving two fragments.

Answer

B. algorithm — The comma before 'which' opens a nonrestrictive interrupter, so it needs a matching comma to close it — without one, the 'which' clause runs straight into the main verb 'describe.'

Answer

C. algorithm: — A colon must follow a complete clause, but everything before the blank is just a long subject phrase, and the colon would also cut that subject off from its verb 'describe.'

Standard English Conventions practice question

Answer: D. algorithm,

Why the other answers are wrong

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