前照灯的()是用来将狭窄的光束折向所要求的方向。
A.灯丝
B.卤钨灯
C.散光玻璃
D.反射镜
参考答案:C
中国近代史上有一位科学家,经过刻苦钻研终于制成纯碱,打破了西方国家对制碱业的垄断,这位科学家是( )
A.詹天佑
B.侯德榜
C.严复
D.魏源
It was only after I came across that matter_______ how important it was to master a foreign language.
A.did I realize
B.had I realized
C.that I realized
D.when I realized