新婚夫妇半年后要孩子。现应选用下列哪一种避孕方法最适宜
A．安全期避孕B．阴茎套C．口服避孕药D．宫内节育器E．皮下埋植避孕
参考答案：B
小明爸爸开的甲乙两个书店出售相同数量的同一种书，甲书店的书卖出了70%，乙书店的书全部卖完，如果把两个书店合起来算，卖出的书占总数的______%．
Three fourth of the homework _______ today .
A．has finished
B．has been finished
C．have finished
D．have been finished
