off-grade的用法和样例：
词汇搭配
- cut off grade 品位下限,边界品位...
- off-grade sponge 不合格海绵金属,不合...
- off-grade iron 等外铁,等外生铁,不...
- off grade metal 等外金属
- off-grade product (砖的) 等外品...
- cut-off grade 品位下限
- off-grade alumina 不合格氧化铝,不合格...
- off-grade metal 不合格金属
- off-grade qualities 等外货
