1.?a challenging problem

2.?be on schedule

3.?lack confident in 在...方面缺乏信心

4.?be like =look like

5.?much more dynamic than 比...有活力的多

6.?the fixed classroom

7.?Fix one’s eyes/attention on

8.?A be substitute for B ?A是B的替代物

9.?stressful?adj.?→?stress n./v.

10.?differ v.?→?different adj.?→?difference n.

11.?confidence n.?→?confident adj.

12.?pressure n.?→?press?v./n.

13.?Recover v.?→?recovery n.

14.?unfortunately adv.?→?unfortunate adj.?→?fortunate adj.?→?fortune n.

15.?a fruitful and satisfying life