阅读下面材料，在空白处填入适当的内容（1个单词）或括号内单词的正确形式。
Dear Li Kang,
How's ____ going? I thought I'd write to tell you______ the American school system. Secondary school in the U.S. usually _______ (cover) seven years, grades six to twelve. Ninth to twelfth grades are high school. At the end of twelfth grade, American students receive the high school diploma. Students need a high school diploma____they want to go to college.
The school year _____ (divide) into two semesters, the first of which is September through December, _______ the second January through May. We have a long summer vacation! We start school at 7:50 am and we finish at 3 pm.
I take part in all kinds of after-school activities—I play football, basketball, _______ (swim), volleyball, table tennis and I go to theater club.
______ you tell me something about your summer vacation and _____ Chinese school system in your next letter?
Best ____ (wish),
Rob Marshall