【单选题】51 单片机执行 MOVC 指令访问片外 ROM 时,相关的信号状态是( )。
A.
PSEN 有效为低电平, EA 有效为低电平。
B.
PSEN 无效为高电平, EA 有效为低电平。
C.
EA 有效为低电平, PSEN 无效为高电平。
D.
EA 有效为高电平, PSEN 无效为高电平。
【判断题】在CS中,确定好灵敏度值后可以通过自动、手动噪声修正等方法进行降噪
【单选题】He ______ a cold last week.
【单选题】Faced with a bill for $10, 000, __________.
A.
John has taken an extra job
B.
the boss has given john an extra job
C.
an extra job has been taken
D.
an extra job has been given to John
【单选题】John got caught by the police ______ at 160 km an hour.
【单选题】With his hard work, John ____ the basic knowledge of computer.A. has caught B. has acquired C. has required D. has acknowledged
【简答题】John has never been on time, ______? A) has John B) hasn't John C) has he D) hasn't he
【单选题】Little John caught a (n)______fish this morning.