A：临洮—咸阳
B：临洮—辽东
C：陇西—辽东
D：临洮—函谷关
A: ____ is the man?
B: ____ is my uncle.
A: How ____ is your ____?
B: My uncle ____ 30.
Security devices at airports are ______ to spot weapons that could be used by terrorists.
15－8=（ ）
小河和小力去买蜡烛，一共买了45根，结果有6根由于质量问题不能点燃，小河又让小力买了4根，最后他们一共有____根能用的蜡烛。
