24V及60V直流电源输出端的杂音计脉动电压值不宜大于().
A.4.1MV
B.1.8V
C.2.4MV
D.2.2V
参考答案:C
关于下列四幅图中解释错误的是( )
A.深秋,我县出现大雾天气,雾气缭绕是水蒸气降温液化形成的
B.火箭升空时,发射架下出现大量“白雾”是水先汽化后液化的结果
C.301国道旁的雾凇景观到中午就消失了,这是雾凇熔化的结果
D.房檐下的“冰溜子”是水降温凝固形成的
Which of the following statements is true of dyslexia a. It is a worldwide problem. b. It is a regional problem. c. It is a social problem. d. It is a biological problem.