问题 选择题 想一想,选一选。( ) 1. 21( ) 2. 40( ) 3. 31( ) 4. 50( ) 5. 45( ) 6. 56A. fifty-sixB. twenty-oneC. fortyD. thirty-oneE. fiftyF. forty-five 答案 1-6 B C D E F A