—Look! The line of people is ______.—Bad luck. I don't think we can get any tickets.
A:hopeless
B:helpless
C:endless
D:careless
食物中的营养物质主要有脂肪、糖类、蛋白质、水、____和维生素六大类.
计算:
4x+5x 3b+b 4a-a 8x-7x
美国南北战争时期,林肯政府的首要目标是( )