因为这几道题大概是同一个知识点 能总结一下更好~
1.Combine each pair of sentences into one sentence,___ the second as an attributive clause.
A.using B.use C.to use D.used
2.He was busy writing the story all the morning ,only ___ off occasionlly to have some tea.
A.breaking B.to break C.having broken D.to have broken
3.Mary is writing a letter to a friend of hers in her room,___ him to her birthday party.
A.having invited B.inviting C.invite D.invited