ALTHOUGH THUNDER AND LIGHTNING ARE PRODUCED AT THE SAME TIME, LIGHT WAVES TRAVEL FASTER ____ SO WE SEE THE LIGHTNING BEFORE WE HEAR THE THUNDER

Tiếng Anh ĐỀ THI THỬ ĐẠI HỌC KHỐI D ANH 2013 PHẦN 2 ĐỀ 2 POTX

20. Although thunder and lightning are produced at the same time, light waves travel faster ____ so we see the

lightning before we hear the thunder.

A. than sound waves

B. than sound waves do

C. do sound waves

D. sound waves.