The selection of English teachers used to be mainly based on ______.

A．never thought of any possible link between stress and illness
B．hardly considered emotional factors when dealing with a patient
C．discovered that the brain and the immune system functioned independently
D．found that diseases were caused by psychological factors

A．research workers are allowed to follow unexpected, interesting clues
B．scientists make a discovery first, and then try to use it
C．it is the man who is given support
D．results of practical value are to be achieved