---I failed to catch the early bus because I overslept this morning．

---You_________have stayed up too late last night．

---I failed to catch the early bus because I overslept this morning．

    ---You_________have stayed up too late last night．

       A．could            B．would        C．should     D．must

---I failed to catch the early bus because I overslept this morning．

---You      have stayed up too late last night．

A．could          B．would           C．should           D．must

---I failed to catch the early bus because I overslept this morning．
---You_________have stayed up too late last night．