读某日太阳光照图(阴影部分为黑夜),完成下列填空
在ABCD四点中,此时正午太阳高度达一年中最大值的是(),B点的正午太阳高度为()。
参考答案:A;66°34′
—Do you know that Jack()a postman for about six years —Yes, I see.
A. has become
B. has turned
C. has changed
D. has been
透平停真空泵时应先关真空阀后关动力蒸气阀。