Question

Frank often wears a mask ________he can keep fit in the foggy and hazy (霾) weather.

A．only if

B．until

C．so that

D．even though

Answer 1

C

解析试题分析：句意：弗兰克经常戴口罩所以他可以在雾霾天气里保持健康。So that引导结果状语从句，only if表示“只要”；even though表示“即使”，until表示“直到”，故选C。
考点：考查连词的用法。