下面两幅图(图一,二)所表达的历史信息,与哪一事件相关联?( )
A:秦国商鞅变法
B:汉代丝绸之路
C:北魏孝文帝改革
D:宋辽澶渊之盟
He stayed America two weeks last year.
常用的水银温度计是根据液体的____ 规律制成的;在烈日当空下的海边沙石热得烫脚,而海水却是凉凉的,这主要是由于海水的 ____ 比沙石的大.
—I will visit my grandparents in Beijing next month. Could you please tell me______?
—Oh, you may take the subway there.