1·Several processes—melting, refining, homogenising—take place simultaneously in the 2000 tonnes of molten glass in the furnace.
熔炉里的2000吨熔融玻璃中，几个过程——熔化、精炼、均质化——在同时进行。
2·Several processes - melting, refining, homogenising - take place simultaneously in the 2000 tonnes of molten glass in the furnace.
几个过程的熔化、精炼、均质化同时发生在2000吨炉中熔融玻璃。