单项选择题
We've tested three hundred types of boots, none of（）is completely waterproof.
A．which B．that C．what D．them
单项选择题 All（）is needed is a continuous supply of fuel oil.
单项选择题 The award was won by Dennis Johnson,（）the coach highly respects.
单项选择题 The two elements（）water is made are the gases of oxygen and hydrogen.
