【单选题】After the trainer was sure that the whale could look after itself, he __________it into the sea.
【单选题】基于非竞争的随机接入模式,一般适应于以下哪种场景
【单选题】某社会工作服务机构面向社区居民开展了一系列活动,带领不同年龄段的居民体验失明、失聪、肢残等多种失能感受。在改善残疾人社会环境方面,这类活动产生的直接作用是( )。
【单选题】After his initial discovery, Baekeland ______.
A.
continued to improve varnish
B.
did many experiments that were aimed at finding a method to shape plastic
C.
did a series of successful experiments and soon worked out a method of molding plastic
D.
did many experiments, the results of which indicated that plastic could never be softened
【判断题】激光器中,谐振腔的作用在于使受激光子沿输出轴方向多次往复反射,相互激发,产生链锁反应,加强和改善激光的输出,得到单色性和方向性很好的激光。
【单选题】r1=-0.95 与r2=0.89,两者的相关程度为:
【简答题】设外部有一脉冲信号源PLUS,要求用8253—5的计数器0对该信号源连续计数,当计数器计为0时向CPU发出中断请求。 1、画出8253-5的CLK0、GATE0和OUT0的信号连接图。 2、若该芯片的端口地址为40H~43H,计数初值为1234H,写出该计数器工作在方式2按二进制计数的初始化程序。 3、若计数初值为12345H,在上述基础上增加计数器1如何连接以实现计数。