用于疑问句 meaning in English

a.at all

" could " is more polite but is only used in questions .
Could更客气些，但只用于疑问句中。
" lately " is used in questions and negative statements .
“lately”用于疑问句和否定式陈述句中。
" could " is more polite but is only used in questions
Could更客气些，但只用于疑问句中。
" lately " is used in questions and negative statements
“ lately ”用于疑问句和否定式陈述句中。