

Many countries have cut the level of lead pollution by banning the use of the metal in petrol. In other countries, its use is very strictly controlled. We have to reduce or get rid of the three other harmful gases produced by the 630 million vehicles worldwide - a(n) ............ that is likely to double in the next twenty
A. form
B. shape
C. figure (tại sao là C vậy)
D. amount
A. form
B. shape
C. figure (tại sao là C vậy)
D. amount