当焊丝外伸长增加时，电阻热也将增加，焊丝熔化加快，因此余高（）。
参考答案：增加
How many minutes will it take to completely fill a water tank with a capacity of 3,750 cubic feet if the water is being pumped into the tank at the rate of 800 cubic feet per minute and is being drained out of the tank at the rate of 300 cubic feet per minute ？（）
A.3 min. 36see.
B.6 minutes
C.7min. 30sec.
D.8 minutes
E.1，875 minutes
过去6个月内已经做出了行为改变，属于行为改变阶段模式中的（）
A.无意图阶段
B.有意图阶段
C.准备阶段
D.行动阶段
E.维持阶段
