【单选题】The boy is taller than ________ in his class.
【单选题】The boy is much____than Jim.
【单选题】我国和大多数国家采用 ( )Hz 作为电力工业标准频率 ( 简称工频 ) 。
【单选题】The boy is working harder than ever, hoping to ___the time he has wasted playing online games.
【单选题】我国和大多数国家都采用 作为电力标准频率(而美国和日本等少数国家采用 60Hz ),这种频率的正弦交流电在工业上应用广泛,因此,也称之为工频。
【多选题】罗马教会和世俗王权之间冲突的第二阶段的标志性事件有( )。