Most animals have little connection with animals of a different kind, _______ they hunt them for food.
A．if B．while C．unless D．as
He loved his family, but seldom _______ spend much time with them.
A．was he able to B．he was able to
C．is he able to D．he is able to
A study shows that walking fast in your old age is a ______ that you will live a long life.
A．sign B．mark C．symbol D．signal
— Where _______ you put my dictionary?
— I left it on your desk when you _______ to Tom.
A．did; spoke B．have; were speaking
C．had; were speaking D．had; spoke
Raising children is said to be a job _______ parents receive the least formal training.
A．in which B．for which C．where D．to what
_______ blood if you can and many lives will be saved.
A．Giving B．Give C．Given D．To give
