A:the bus driver was asked to hel
B:the bus was searched
C:it was looked for everywhere
D:David called for hel
物体处于平衡状态,下列说法中正确的是()
亚洲与北美洲的洲界线、俄罗斯与美国的国界线和国际日期变更线,“三线”穿过的海峡是()