IT IS SAID THAT POLLUTION IS ONE OF THE MOST SERIOUS PROBLEMS TO SOLVE

50. - DE THI TA 50. - DE THI TA
DE THI TA

50.It is said that pollution is one of the most serious problems to solve.

Pollution ………..

A. is said to be one of the most serious problems to solve.

B. was said to be one of the most serious problems to solve.

C . is said to have been one of the most serious problems to solve.

D. is being said to be one of the most serious problems to solve.

THE END.

Keys.