已知向量a=(0,0,1),b=(0,1,1),则a与b的夹角为 [ ]
A、0°
B、45°
C、90°
D、180°
答案:B
想一想,选一选。
1. 当你问别人“全家福上都是谁”时,你应说:[ ]
A. Who are they?
B. Who is it?
2. 当你想告诉别人“我家有三个家庭成员”时,你应说:[ ]
A. My family has four members.
B. My family has three members.
3. 当你向别人介绍你叔叔的体貌特征时,你可以说:[ ]
A. My uncle is thin.
B. My uncle likes music.
存款货币是指能够发挥货币作用的银行存款,主要是指能够通过签发支票办理转账结算的( )。
A.定期存款
B.定期和活期存款
C.零存整取存款
D.活期存款