用法:
1 [U, C] substance usedto prime3(2) a surface for painting （上油漆用的）底层涂料, 底漆.

用法:
2 [C] amount of explosive in a smallcontainer used to explode the main charge of gunpowderin a cartridge, bomb, etc 底火; 火帽; 点火药.

• before long(long before)
• before(for)
• before(in front of)
• before(previously)
• before(prior to)
• before(till)
• begin(begin with)
• begin(start)
• behind time(behind the time, behind the times)
• behind time(behind the time, late for)
• behind time(later for)
• believe(believe in)
• beloved
• beloved(loving)
• below the mark(beside/wide of the mark)
• below(under)
• beneath notice(under notice)
• beside oneself(by oneself)
• beside the mark(off the mark)
• beside the mark(wide of the mark)
• beside the point(off the point)
• beside the question(beyond question)
• beside(besides)
• beside(by)
• beside(past)