初中的用法和样例：
例句
-
经过五年的艰苦工作，他们完成了一套高质量的教材。该书分为六级，从小学4年级到初中3年级。
After five years of hard work they presented a high quality textbook, which consisted of six levels from grade4 to grade9. -
他正在上初中。
He is studying at a junior middle school.
