So sánh các phân số sau:

a ) − 4 7   + 3 − 7     v à     1 ; b ) 3 5     v à     2 3 + − 1 5 . c ) 1 14 + − 4 7       v à     1 6 + − 3 4 ; d ) 1 2   + 2 3 + 3 4 + 4 5 + 5 6 v à     4

I accidentally _______ my ex and his girlfriend when I was walking along a street yesterday.

A. lost touch with

B. kept an eye on

C. paid attention to

D. caught sight of

Tính nhanh: 18.15 + 35 + 15.32 + 35.49.