单项选择题
某井泵深为800m，冲程为3m，冲次为6次／min，含水率为45％，抽油杆在空气中每米质量为3．24kg，在液...
未知题型某井泵深为800m，冲程为3m，冲次为6次／min，含水率为45％，抽油杆在空气中每米质量为3．24kg，在液体中每米质量为2．73kg，活塞截面以上液体每米质量为2．12kg。求该井悬点最大载荷（精确到0．01）。
Some people would rther ride bicycless bicycle riding h...
单项选择题Some people would rther ride bicycless bicycle riding hs _____ of the trouble of tking bus
In Britain, freedom of the press is protected, though t...
判断题In Britain, freedom of the press is protected, though there is still censorship of thIn Britain, freedom of the press is protected, though there is still censorship of the press.（）
