A_______is a purposeful collection of materials assembled over a period of time by a learner to provide evidence of skills，abilities related to his／her study．

[单选题]If over a period of time, the oi1 film partially disappears, so that dry areas are formed on the cylinder wall, these areas and the piston surfaces will by frictional interaction, become finely scuffed and hardened, iegood mirror surface" will have

[单选题]An analyst is investigating the performance of three portfolio over the sam

[单选题]An analyst gathered the following information about the monthly returns ove

[单选题]If over a period of weeks the air-box pressure of a turbo-charged, diesel engine, operating at full load, appears to be dropping off, the cause can be （）.A . open air-box drainsB . loss of cooling water to the diffuserC . gradual fouling of the air f

[单选题]At one time this view ____ over the academic circles.A. controlled B. domineered C. dominated D. charged

[单选题]Measles ______a long time to get over.A.spendB.spendsC.takeD.takes

[试题]Time was when biologists somewhat over worded the evidence that these creatures preserve the health of game by killing the physically weak,or that they prey only on “worthless species。

[单选题]Measles （麻疹） ________ a long time to get over.A.spend B.spends C.take D.tak

[单选题]Measles(麻疹) ________ a long time to get over.A.spendB.spendsC.takeD.takes

[单选题]Over a given period, the price of a commodity falls by 5.0% and the quantit