RS-232C标准规定其逻辑“1”电平为()。
A.-5V~0V
B.0V~+5V
C.-3V~-25V
D.+3V~+15V
参考答案:C
婴儿期的特点除外()
A.蛋白质需求高
B.易患营养及消化紊乱疾病
C.最易发生意外伤害
D.易发生传染病或感染性疾病
E.生长发育迅速
A.The refrigerator was repaired by an old man.
B.The refrigerator will be fixed if it is under warranty.
C.Mrs. Green had her refrigerator fixed for nothing.
D.Mrs. Green would have had the refrigerator repaired if she had warranty.