His parents often __________ (吵架) about money, which made him upset.
They set out to __________ (积累) a huge mass of data for the research.
Class and social __________ (地位) is of importance in ancient China.
His sick father is becoming a__________ (负担).
The company made an __________ (调整) in my salary.
The movements of machines are a__________, you only need to start and stop the machines.