THE AIR NOW IS NOT AS PURE AS IT__________ .A. IS USED TO BEING B....
23. The air now is not as pure as it__________ .
a. is used to being b. used to be
c. was used to
d. is used to be
23. The air now is not as pure as it__________ .
a. is used to being b. used to be
c. was used to
d. is used to be