Correct Answer: C

Rationale: The correct answer is 'C: con-'. The prefix 'con-' means 'with', indicating being together or having a connection. - 'Bio-' means life or living organisms, not 'with'. - 'Per-' means through or completely, not 'with'. - 'Trans-' means across or beyond, not 'with'. Therefore, 'con-' is the only prefix among the options provided that signifies the meaning 'with'.

Correct Answer: B

Rationale: The correct answer is B, 'He ate a lot on vacation, but he did not gain any weight.' The conjunction 'but' is used to show a contrast between the two clauses. Choices A, C, and D do not effectively demonstrate the contrast between eating a lot and not gaining weight, making them incorrect. Choice A introduces a conditional relationship that is not present in the original sentences. Choice C implies a causal relationship that is not intended. Choice D also suggests a causal link that is not appropriate given the context.

Correct Answer: C

Rationale: The correct plural of 'century' is 'centuries'. In English, to form the plural of most nouns ending in -y, you change the -y to -ies. Choice A, 'Centurys', is incorrect because it does not follow this rule. Choice B, 'Centures', is also incorrect as it does not provide the correct plural form. Choice D, 'Centuryies', is a completely incorrect and non-standard plural form of 'century'. Therefore, the correct answer is 'Centuries'.

Correct Answer: A

Rationale: The correct answer is A. The sentence is missing quotation marks around 'When is the assignment due?'. Quotation marks are essential to indicate that the words enclosed are being directly quoted. Choice B is incorrect because a semicolon is not needed in this context. Choice C is incorrect as a comma is already present after 'He asked' to separate the introductory clause. Choice D is incorrect because the sentence does lack proper punctuation, which are the quotation marks.

Correct Answer: D

Rationale: The correct answer is 'D' because the conjunction 'Although' conveys contrast and shifts the focus to emphasize that puppies require a lot of work despite being fun-loving. Choice A uses a semicolon, which does not emphasize the contrast needed in the context. Choice B introduces a causal relationship, not the intended contrast. Choice C uses 'Since,' which implies a causal connection rather than the desired contrast, making it incorrect.