小明同学使用显微镜观察人体口腔上皮细胞,他想让视野中看到的细胞数目最少,应该选择的镜头组合是( )
A:①④
B:①⑤
C:③④
D:③⑤
1937年,毕加索为抗议德国法西斯轰炸西班牙小镇而创作的作品是( )
若函数y=(3-m)xm2-8是正比例函数,则常数m的值是( )
His wife, to whom he _____ for 20 years, died of cancer last Thursday. ( )