— Linda, I called you this morning, but nobody answered the phone.
—I'm sorry. I ________ football with my friends then.
A:play
B:played
C:am playing
D:was playing
如图所示,图中共有相似三角形( )
设F1,F2是双曲线x2-y224=1的两个焦点,P是双曲线上的一点,且3|PF1|=4|PF2|,则△PF1F2的面积等于( )
下图是英国部分年代棉纺织品出口价值变化示意图,导致这种变化的主要因素是()
已知函数f(x)=ax3+bsinx+4(a,b∈R),f(lg(log210))=5,则f(lg(lg2))=( )
She could speak ________ Japanese ________ Chinese, so I had to talk with her in English.