Smith failed to ______ for the deficit in the company's hank balance.

Difficult as it is, English study is in the long run __...

单项选择题Difficult as it is, English study is in the long run ______ to a learner in his or her career development.

Cigarette smoking is a great health ______ and may lead...

单项选择题Cigarette smoking is a great health ______ and may lead to fatal diseases.