发生塑性变形的轮齿在从动轮上发生（）。

A．凹痕

B．凸棱

C．擦伤

D．涂抹

The demonstrators demanded ________.

A．for the release of jailed Solidarity leader Lech Walesa

B．to suspend the Solidarity Labour Union

C．to mark the anniversary of a workers revolt

D．for the punishment of those killers