胸骨后前位（）
A．平静呼吸下屏气
B．深吸气后屏气
C．深吸气再呼出后屏气
D．平静呼吸不屏气
E．缓慢连续呼吸
参考答案：E
用所给单词的适当形式填空。
1. Let's stop _____ (have) a rest.
2. Please stop _____ (talk). The teacher is coming.
3. He is too young _____ (go) to work.
若土地年纯收益不变，土地还原率不变且大于零，则无限年期土地使用权的价格计算公式为( )。
A．P=a/r B．P=a/(r±s)C．P=a/r±b/r2 D．P=a/r[1-1/(1+r)n]
