The door's locked, so plainly they must be out.

这门锁着，明摆着他们不在。

Supposing he is not at home, what then?

他不在,那怎么办?

Ask if he is at home.

问一问他在不在。

Not normally home cooked but bought at a fish and chip shop ("chippie" in north of England) to eat on premises or as a "take away" or as US would say "to go".

通常不在，但熟食买一条鱼芯片店（ “薯条”在英格兰北部的）吃的处所或“拿走”或美国会说“去” 。