银行汇票的实际结算金额不得更改，更改实际结算金额的银行汇票无效。( )
参考答案：对
改写句子。
例: A bird can fly. → Can a bird fly?
1. A cow can walk. → _____________________
2. A fish can swim. → _____________________
3. A rabbit can hop. → _____________________
4. A teacher can write. → _____________________
5. A cat can walk. → _____________________
后牙Ⅱ类洞制备时，鸠尾峡宽度正确的是（）
A.颊舌牙尖间距的1/4
B.颊舌牙尖间距的1/4~1/3
C.颊舌牙尖间距的1/3~1/2
D.颊舌牙尖间距的1/2~2/3
E.颊舌牙尖间距的2/3~3/4
