题目

– Whose notebook is this? -- It _____ Tom. I saw he used it just now. A. must belong to         B. can’t belong to         C. might be belonged to 答案：A解析: 略 如图所示,△ABC中,∠ACB=90°,CD⊥AB于D,且AB+BC=18cm,若要求出CD和AC的长,还需要添加什么条件?