____, Sam knows lots of things about philosophy.

Today the energy problem becomes critical. It ____ an immediate solution.

Dr. Zhang was always ____ the poor and the sick, his private clinic often providing them with free medical care.

For each blank in the following passage, there are four choices marked A, B, C and D. Choose the one that is most suitable and mark your answer by blackening the corresponding letter on the Answer Sheet.

22________

23_________