[英文] 唔知點講....

a is fastest
b is the second fastest
c is the third fastest (second slowest)
d is the slowest

in one sentance:
a is the fastest, followed by b and then c, and lastly d.
or
from fast to slow is a,b,c,d.

the speed of a is the fastest, b is second, c is third, and d is the slowest.

a is the fastest/ the most rapid, b is the second, then follow by c, d is the slowest. OR
a is faster than b, b is faster than c, d is the slowest