Whose trousers are these?
因为原句中是 his trousers(他的裤子),而划线提问中trousers,前面有一个空格,所以应该是“谁的”裤子,填whose.句子其他的成分不变,只需要把谓语are提前到主语these前面就行,所以是 are these.
Whose trousers are these?
因为原句中是 his trousers(他的裤子),而划线提问中trousers,前面有一个空格,所以应该是“谁的”裤子,填whose.句子其他的成分不变,只需要把谓语are提前到主语these前面就行,所以是 are these.