1¡¢I would like to express my warm welcome to all of you on b___ of my school .
2¡¢The teacher asked the students to read the text and u___ the words that they did not understand .
3¡¢If David does not m___ his ways , he will not be able to graduate .
4¡¢I am only worried about his attitude to the job , his c____ is not in question .