题目

With lots of new words , he decides to read them every morning. His teacher said, only if doing it make it. A . to recite; you keep on; can you B . to recite; do you keep on, can you C . recited; do you keep on; you can D . recited; you keep on; you can 答案：A若∠A+∠B=90°，∠B+∠C=90°，则∠A_______∠C，理由是__________．若∠1+∠3=180°，∠2+∠4=180°，且∠1=∠4，则∠2________∠3，理由是_________．