【单选题】药物对于健康人并没有直接的价值,而对于病人则具有直接的价值。这说明价值具有()
【单选题】根据注意的功能,可以把注意分为:选择性注意、持续性注意、( )。
【简答题】there is considerable 8 about what concentrations or periods of exposure are necessary to produce specific health problems.
【单选题】药物对于健康人并没有直接的价值,而对于病人则具有直接的价值,这突出地说明了价值具有的
【简答题】______ would be reduced slightly if CO2 concentrations stabilised at around 550 ppm.
【简答题】found in homes and which occurs from the 10 concentrations that occur for short periods of time.
【单选题】We can infer from the passage that ______.
A.
concentrations of greenhouse will become worse
B.
concentrations of greenhouse will become better
C.
generally there is no rain in Antarctica
D.
the North Pole is no longer covered with ice