--tom is not feeling very well --he seems to have a cold --- the weather changes suddenlya\ beforeb\ soc\ becaused\ though说理由!

--tom is not feeling very well --he seems to have a cold --- the weather changes suddenlya\ beforeb\ soc\ becaused\ though说理由!
--tom is not feeling very well --he seems to have a cold --- the weather changes suddenly
a\ before
b\ so
c\ because
d\ though
说理由!

--tom is not feeling very well --he seems to have a cold --- the weather changes suddenlya\ beforeb\ soc\ becaused\ though说理由!
选c 翻译是 汤姆感觉身体不太舒服,他好像感冒了,因为天气变化的太快.是因果关系,结合语境带入呼之欲出