问题
判断题
螺旋密封属于接触式动密封。（）
答案
参考答案：错
解析：螺旋密封属于非接触式动密封。
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螺旋密封属于接触式动密封。（）
参考答案：错
解析：螺旋密封属于非接触式动密封。
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| Canada is the second largest country is the world. It is over 7,000 kilometres from the __1__ coast to the east. It __2__ six time zones. __3__ it is 9 a. m. in Vancouver on the west coast,it is 1:30 p, m. in St John's on the east coast. English and French __4___ the two main languages in Canada. About 60 percent of __5 _ people speak English, and about 25 percent speak French. More __6_ 70 percent of its population live in cities near the US border (边缘). Ottawa is the capital. Every year millions of tourists go there to __7__ museums and take part in the cultural activities. Toronto is the largest city of the country __8__ about 2. 5 million people. Montreal is __9_ second biggest French-speaking city in the world. The maple leaf (枫叶) is the national symbol of Canada. The Canadian flag has a red maple leaf on a red __10_ white background (背景). | ||||
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