－Jeffery seems to go without proper food and sleep for days.
－Leave him alone.That's________he reacts to a lost love.
A．what B．how
C．why D．when
She________the opportunity，but unfortunately she just let it go.
A．should have taken B．must have taken
C．needn't have taken D．can't have taken
I don't remember who came first，but we all________the lecture.
A．attend B．attended
C．have attended D．are attending
We can't avoid negative thoughts，but we should make it a habit to replace each negative thought with a positive________．
A．one B．ones
C．the one D．that
Clive Palmer，the designer of Titanic II，________to answer questions about the project's cost.
A．abandoned B．declined
C．decreased D．regretted
The couple's birthday this year happened to fall on ________ same day，________Monday in September.
A．the；/ B．a；/
C．a；the D．the；a
