题目

阅读理解Whenwe learn to drive, we need to learn basic skills such as how to switch on theengine, turn on the wipers, operate the brakes, etc. before we actually take tothe road. Once the lower order operations and skills listed above have beenautomatized or at least routinized to the extent that we do not have to payattention to them (by­pass Working Memory's attentional systems), we canactually be safe in the assumption that we can wholly focus on the higher orderskills which will allow us to take the split seconds decisions that willprevent us from getting lost, clash with other cars, b如图①，AB是⊙O的直径，AC是弦，直线EF和⊙O相切于点C，AD⊥EF，垂足为D．（1）求证：∠DAC=∠BAC；（2）若把直线EF向上平行移动，如图②，EF交⊙O于G、C两点，若题中的其它条件不变，这时与∠DAC相等的角是哪一个？为什么？