多项选择题 保证有效沟通需要注意（）。

单项选择题 Which way does the following paragraph use to start a topic?Many people smoke. They smoke because they think it makes them cooler and it is a good way for them to show their manhood.

单项选择题 Please fill the blanks of the following sentence from the following answers.He is ________ to the computer day and night.