单项选择题
When they ______ the bus, the boys and girls were carrying sandwiches and wine. A．board B．boarded C．board on D．boarded on
单项选择题 我国著名书画家、篆刻家、西泠印社创始人吴昌硕于1844年诞生在( )。 A．杭州孤山 B．上海市 C．安吉县 D．余杭超山
单项选择题 浓溶液稀释成稀溶液时保持不变的是( ) A．溶剂的量 B．溶质的量 C．溶液的量 D．溶液的浓度
单项选择题 He could see that she ______ patient all her life. A．was B．were C．had been D．has been
