13.Being a Senior three student,he will never let his parents down(使父母失望).
14.Having finished his homework,he went to bed.
15.Running,biking and swimming are popular in summer.
16.It took us only five yuan to buy this pen.This pen just costs five yuan.I only spent five yuan on/(in) buying this pen.I only paid five yuan for this pen.
17.It is said/reported/considered/thought that the more pressure you have,the worse result you will get.
