用括号内所给动词的适当形式填空.    
When I came into the classroom，Mr．Li         (clean)the blackboard．
The boy found a purse         (1ie)on the ground and picked it up．
Would you like         (have)a try?
Tina hopes she can         (invite)to Mary's birthday party．
Mr.Wang finds stamps fascinating．He         (collect)them for many years．