抛物线y=-x2-2x的开口向______,与y轴交于点______.
∵a=-1<0,
∴抛物线开口向下,
令x=0,得y=0,抛物线与y轴交于点(0,0),
故填:下,(0,0).
Now that their parents are dead, the poor boy doesn't know ______ the money they left. [ ]
A. how to do with
B. what to do with
C. to do what with
D. how he will do with
投保人对保险标的应当具有(),这是保险合同有效性的前提。
A.保险利益
B.保险关系
C.占有关系
D.经济利益