适合危重支气管哮喘的治疗手段是（）

A.高PEEP

B.液体通气

C.氦氧混合气辅助通气

D.腹卧位通气

E.体外膜肺

What’s the difference between Wal-Mart in China and in USA().

A. It’s not big.

B. Trust-Mart is a branch of Wal-Mart.

C. Wal-Mart permits labor unions into its stores.

D. Wal-Mart is loath to give discounts.