单项选择题
Lisa was busy taking notes （） Mark was searching the Internet for information.
A.until B.unless C.while D.if
单项选择题 "Whenistheconcertsupposedtostart？""It（）now."
单项选择题 （）Yourhelp，Iwouldnothavesucceeded.
单项选择题 Itisno（）talkingtohimbecausehewillneverchangehismind.
