.It is that he has been addicted to the drugs and has difficulty quitting it.A. obviouslyB

问题补充：

.

It is that he has been addicted to the drugs and has difficulty quitting it.

A. obviously

B. apparently

C. possibly

D. likely

答案：

A. obviously

B. apparently

C. possibly

(答案→)D. likely

解析：词义辨析题。A. obviously 显而易见 B. apparently明显 C. possibly 可能（副词） D. likely 可能（形容词）句意：他可能吸毒上瘾了戒掉它很难。根据语境此处缺少形容词故选D