面向对象方法中，核心是 【9】 ，它具有理想的模块机制，独立性好。
参考答案：类(对象)
When the earthquake, a destructive natural disaster, happened, ninety-nine coal miners were trapped
in the coal mine _____the ruins, waiting _____.[ ]
A. in; to be rescued
B. under; for being rescued
C. in; to rescue
D. under; to be rescued
Suppose the price of computers increases from $1000 to $1200. Assuming the original quantity demanded for computers was 50 million units, and the new quantity demanded is 45 million computers, what is the price elasticity of demand, and is the demand for computers elastic or inelastic（）
A. 0.58,
B. -0.58,
C. 1.73,
