【简答题】The only real and lasting solution, say the experts, is to convince people that driving is a skilled task requiring constant care and concentration.
【简答题】A solution is 0.010mol·L -1 in both Cu 2+ and Cd 2+ . What percentage of Cd 2+ remains in the solution when 99.9% of the Cu 2+ has been precipitated as CuS by adding sulfide?
【单选题】AIDS is a global problem that demands a unified, worldwide solution, which is not only the responsibility of nations in which AIDS is most __________.