________left the door unlocked must be held responsible for the accident.
This memorial was built ______ those heroes who laid down their lives for the liberation of the black.
The news reporter hurried to the airport, only_________ the film stars had left .
Although there were so many people in the square, I could ______ my friend.
What worried the child most was ______ to visit his brother n hospital.
What the doctors really doubt is ______ my mother will recover from the serious disease soon. A.when B how C whether D why