选择正确答案填空完成句子。

1. I often play _____________ (a, the, / ) football.

2. He often plays _____________ (a, an, the) guitar.

3. I _____________ (sometime, sometimes) watch TV in the morning.

4. Look at Jenny. She is singing _____________ (loud, loudly).

5. Do you usually help your mother _____________ (do, doing) the housework?

诊断纵隔气肿的主要依据是（）。

A．有气胸病史

B．胸部有皮下捻发感

C．心尖部可闻及与心搏同步的气泡破裂音

D．有胸骨后疼痛、呼吸困难、发绀等症状

E．X线在纵隔旁可见透光带