1．_____ X—rays were first discovered by ______ German scientist , Wilhelm K. Rontgen , in 1895 , almost by accident .
A．/, a , / B．The , a, an C．The , the , / D．/, the , the
2．Our class will certainly win the tug-of-war , because all the classmates are highly _______ .
A．selected B．focused C．motivated D．promoted
