关于能量单位叙述正确的为()。
A.1kJ=0.239kcal
B.国际通用单位为焦耳
C.1kJ=4.184kcal
D.通常用卡作单位
参考答案:A, B
—Have you seen my e-mail about our TESL project?
— Yes. Luckily I checked my e-mails yesterday. Normally I ______ my e-mail box for days. [ ]
A. don't open
B. didn't open
C. hadn't opened
D. haven't opened
为了防止已存有信息的软盘被感染,应采取的措施是( )。
A.保持软盘清洁
B.对软盘进行写保护
C.不要将有病毒的软盘与无病毒的软盘放在一起
D.定期格式化软盘