up-down counter 可逆计数器 ; [计] 升降计数器 ; 计数器
up down counter 可逆计数器
up-and-down counter 增减计数器
UDC Up C Down Counter 加减计数器
down up counter 可逆计数器
She walks up to the counter, SLAMS a book down and screams at the librarian, - "This is the WORST book I've ever read!"
她走向柜台，砰的一下把书摔到上面然后冲着馆长嚷到，-“这是读过的最烂的书了！”
She sank down on one of the little stools behind the counter of the booth and looked up and down the long hall which, until this afternoon, had been a bare and ugly drill room.
她坐在摊位柜台后面的一条小凳子上，前前后后地观看那个长长的展览厅，这地方直到今天下午以前还是个空空荡荡难看的教练厅呢。
The horizontal line's counter is also activated by this signal to control galvanometer up and down.
此脉冲信号还是行计数器的触发信号，间接地控制振镜场扫的正程和逆程。
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