【单选题】.某人的血细胞与B型血的血清凝集而其血清与B型的血细胞不凝集,此人血型为
【单选题】某人的血细胞与B型血的血清凝集而其血清与B型血的红细胞不凝集,此人血型为:
【单选题】Now I spend time _____ what I love to do. [ ]
【单选题】Not only good about helping other people, but I get to spend time doing what I love to do. [ ]
【单选题】I spend a lot of time online
【单选题】I spend much more time playing basketball than I _______ for my lessons.
【单选题】—How's your weekend, Jack? —I spent all time _____ my friends. But sometimes I spend time _____ the internet. [ ]
【单选题】Now I spend time what I have to do. [ ]
【多选题】下图是74157的芯片引脚图,下列说法正确的是()
B.
74157要数据选择功能,15引脚芯片使能端要接地。
C.
74157芯片16引脚接+5V,8引脚及15引脚接地后,当S=0时四个2选1数据选择器同时工作,即4引脚选择2引脚输入数据输出,7引脚选择5引脚输入数据输出,9引脚选择11引脚输入数据输出,12引脚选择14引脚输入数据输出。
D.
74157芯片16引脚接+5V,8引脚及15引脚接地后,当S=0时四个2选1数据选择器的Y输出为0。