It's a good habit to wash your hands _____ you have meals.
句意为:在你用餐前洗手是个好习惯。根据语境可推测,空处引导时间状语从句且表示“在......之前”。unless 意为“除非”,引导条件状语从句;while 意为“当......时候”,引导时间状语从句;when 意为“......时候”,引导时间状语从句;before 意为“在......之前”,引导时间状语从句。故选D。
— Would you like _____ to eat?
— Yes,please.
形容词修饰复合不定代词时,形容词要后置,先排除选项B;在表示邀请、请求或期待得到肯定回答的疑问句中要用 something。故答案为选项C。
— If you have any problem,you can always ask me _____ help.
— Thank you.
根据 ask sb. for help 的固定搭配可知答案为选项C,该短语意为“向某人求助”。