Laser/ device/ concentrate/ light waves/ intense/ beam

Câu hỏi :

Laser/ device/ concentrate/ light waves/ intense/ beam.

A. Laser is a device concentrating light waves into an intense light beam.

B. The laser is a device concentrating light waves on an intense light beam.

C. The laser is a device which concentrates light waves into an intense light beam.

D. Laser is a device which concentrates light waves to an intense light beam.

* Đáp án

B

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