【单选题】Using superposition principle, when the voltage source isnotactive,itshould be replaced by _________
【简答题】The other lead (read) the amount of oxygen in your blood .
【简答题】We’ve used the wind as an energy source for a long time. The Babylonians and Chinese were using wind power to pump water for irrigating crops 4,000 years ago, and sailing boats were around long before...
【多选题】以下关于螺纹加工方法说法正确的是( )
A.
用丝锥在内孔表面上切削加工内螺纹的方法是攻螺纹
B.
用板牙在外圆表面上切削加工外螺纹的方法称为套螺纹
【单选题】They found that people using the sites exhibited "a form of skimming activity", hopping from one source to another and rarely returning to any source they'd already visited.
A.
The site visitors like exhibiting activity.
B.
The site visitors seldom return to any source they’d already visited.
C.
The site visitors have a reading habit that they enjoy staying on the site for hours.
D.
The site visitors like some of the sources but not all of them.
【单选题】Which of the following is one of the main advantages of using statistical reports as the source of information?
A.
Statistical reports can be used to obtain firsthand knowledge.
B.
Unfiltered information can be obtained using statistical reports.
C.
Statistical reports are effective for showing relationships.
D.
Statistical reports allow verbal and non-verbal feedback.
【简答题】成形面主要加工方法有()、仿形法加工、()以及在数控机床上加工等。