(2019安徽)Our business won't improve ________ we offer better services to our customers.
A.because B.unless C.after D.since
(2020原创)I respect my parents, ________ sometimes I just can't agree with their old opinions.
(2020原创)My parents were not at home, ________ I had to look after my 5yearold sister.
(2020原创)You may do the survey yourself ________ work with someone else together.
(2020原创)W________ my mom and I were talking about my father's birthday surprise, he came in.
(2020原创)The soup tastes terrible b________ I put too much salt into it.