题目

气体分子中的极性键在红外线的照射下，易像弹簧一样做伸缩和弯曲运动，从而产生热量造成温室效应。下列不属于温室效应气体的是 A．CO2 B．N2O C．CH4 D．N2 答案：D ______ in the chimey for five hours, the thief looked very pale and tired. A.Having been trapped 　    B.Being trapped 　 C.trapping　　      D.Having trapped