单项选择题 “教师语言不是蜜,但可以粘住东西。教师语言不是蜜,但可以牢牢粘住学生的注意力,引导他们在知识的海洋里扬帆起航,引导他们追求生活的真谛,奋然前行”,这句是( )说的。 A. 叶圣陶 B. 魏书生 C. 于漪 D. 苏霍姆林斯基

单项选择题 5. 欲获得频率稳定度高的脉冲信号，应采用（ ） A、单稳态电路 B、集成555 C、对称多谐振荡器 D、石英晶体振荡器

单项选择题 By mentioning 'the figures are as changeable as a mirage in the desert', the author is talking about ______.A.the wealthy people who live atop the wells in the GulF.B.the planet's future fossil-fuel supplies.C.the inconsistent estimates on oil deposits in the GulF.D.the oil traded in the international markets.