A. I often paint pictures.        B. I like winter best.

C. We go to the park at 7:00 a. m.      D. Because there are beautiful flowers.

Which of the following words matches the sound /'sɪŋɡl/?

“春节”“中秋节”都是中国传统节日，但现在有许多西方节日传入我国。如“圣诞节”、“复活节”、“感恩节”。你知道这些节日与哪一宗教有关吗（     ）

解方程：$\sqrt{x+7}$-$\sqrt{x}$=1．