According to the passage, which of the following should be encouraged to enhance learning of math and science
1. Problem solving.
2. Actual research.
3. Repetitive in-class drills.
4. Group work.
5. Rote learning.

A．may be removed from his present post in Iraq
B．may be appointed as the top U.S. commander in Iraq
C．is responsible for the prisoner abuse in Iraq
D．is in disagreement with the Pentagon

A．the U.S. has detected an Iranian spy service network
B．the U.S. has broken the codes used in Iranian spy communications
C．the U.S. would improve its ability to gather intelligence on Iran
D．an Iraqi politician has revealed important intelligence to Iran