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.

单项选择题 若x是int型变量，且有下面的程序片段： for(x＝3；x＜6；x++)printf(x%2)?('* *％d')：(”# #％d/n”)，x)； 上面程序片段的输出结果是 ( )A.* * 3 # # 4 * * 5B.# # 3 * * 4 # # 5C.# # 3 * * 4 # # 5D.* * 3 # # 4 * * 5