ⅡI.单词拼写 1.Your mother t tongue_is the language that you learn from yourparents when you are a baby. 2.The students are expected to do five experiments eachssemester 3.At present,the ssubway_plays an important role in the city'stransportation system. 4.Fire extinguishers(灭火器) are located on each floor and in eacha apartment