Many people are still in habit of writing silly things in public places.A. the; theB. 不填；不

问题补充：

Many people are still in habit of writing silly things in public places.

A. the; the

B. 不填；不填

C. the;不填

D. 不填；the

答案：

A. the; the

B. 不填；不填

(答案→)C. the;不填

D. 不填；the

解析：句意：许多人仍然还有在公共地方写糊涂字的习惯。have the habit of有……的习惯，the表示特指；public places为复数名词短语，前面不需要冠词。故选C。