Among the earliest telescopes were Galilean telescopes, modeled after the simple instrutments

Câu hỏi :

Mark the letter A, B, C, or D on your answer sheet to show the underlined part that needs correction.

A. having used

B. telescopes

C. modeled

D. were

* Đáp án

* Hướng dẫn giải

Đáp án là A. having used => to have used. Vì sau “the first.”, ta dùng to V.

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