Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questionsThe researchers developed the first flu vaccination recently. There was a reliable protection against flu in this country

Đáp án:A

Kiến thức : Kết hợp câu – Đảo ngữ

Giải thích: The researchers developed the first flu vaccination recently. There was a reliable protection against flu in this country.( Các nhà nghiên cứu đã phát triển vắc xin cúm đầu tiên gần đây. Có một sự bảo vệ đáng tin cậy chống lại bệnh cúm ở đất nước này.)

A. Not until the researchers developed the first flu vaccination recently was there a reliable protection against flu in this country.

Cấu trúc: Not until + S + V + trợ động từ +S+  V + …

B. Scarcely the researchers developed the first flu vaccination recently when there was a reliable protection against flu in this country. àsai cấu trúc

Cấu trúc: scarcely +had + S + PII + when + S + Ved

C. But for the first flu vaccination, there wouldn’t be a reliable protection against flu in this country. à sai ý

D. So reliable was the protection against flu in this country that the researchers developed the first flu vaccination recently.

Cấu trúc: So + adj + be + S + that + clause quá đến nỗi mà