Charcoal had been the main fuel of smelting and casting industry before ( ).
举一反三
- 听录音，回答问题并填空1. According to the World Bank, what will global warming cause? It says global warming will _________________ and fuel the spread of malaria and _________________.2. When had the report been released? That report had been released ___________________ before a UN climate summit in Paris.
- The old lady had never been _________ before .
- The classroom _______ cleaned before the teacher came in. A: was B: has been C: had D: had been
- Before the prom, she had been my date for a long time.
- Heath Ledger had been drinking a lot before he died.