题目

There is growing tendency among middle-school students___________they will do some voluntary work during their vacation.        A．which       B．why  C．how  D．that 答案：D家鸽处于不同季节的体温 [　　] A．总体维持在42℃左右B．总维持在37℃左右 C．冬季体温低，夏季体温高D．环境不同，体温不同