可以用角向磨切割钢筋。（）

语法填空。

     Long ago, near the frontier lived an old man. One day he found his horse   1 _ (miss). It was said that the horse was seen running outside the border of the country. The neighbors came to comfort him for the unfortunate loss. But the old man was    2_ (expect) calm and said, “ It doesn’t matter; it may not be a bad event, on the contrary, I think it can be a good    3   .”

     One night the old man heard some noise of horses and got up to take a look. To his surprise, he saw   4   handsome horse besides his own. It was clear that his horse had brought a companion home. Hearing the news, the neighbors all came to say congratulations   5   his good luck. However, the old man was very calm. He added, “It is true that I got a new horse for nothing, but it is hard to say  6  it is good or bad. It may be   7  unlucky thing.”

     What he said turned   8  to be right. The son of the old man was very fond of the horse   9  (bring) home, and one day, when he was riding the horse, he fell off the horseback and terribly hurt in his left leg. “Nothing serious,” the old man said, “perhaps it is going to be good.”

     A year later, many of the youth were recruited (应征) to fight in a war and most of them died. The son of the old man was absolved(免除) from the army service for his   10  (disable), so he escaped death.

税务机关应当根据（）的原则，积极推广使用支票、银行卡、电子结算方式缴纳税款。

A.方便

B.快捷

C.安全

D.及时

中等深度以上龋，银汞合金充填时需垫底，其原因为银汞合金有

A．牙髓刺激性

B．流动性

C．传导性

D．膨胀性

E．收缩性

制冷剂过热蒸汽在冷凝器中放出的热量主要是（）。

A.显热

B.潜热

C.全热

D.摩擦热

柴油发动机高压油泵把输油泵送来的燃油提高一定的压力，并按一定的顺序将适量的柴油送到（）。

A、喷油器

B、化油器

C、火花塞