$A + B$ means $A$ is the son of $B$; $A - B$ means $A$ is the wife of $B$; $A \times B$ means $A$ is the brother of $B$; $A \div B$ means $A$ is the mother of $B$; and $A = B$ means $A$ is the sister of $B$.
What does $P + R - Q$ mean?

$A$ family consists of six members $P, Q, R, S, T,$ and $U$. There are two married couples. $Q$ is a doctor and the father of $T$. $U$ is the grandfather of $R$ and is a contractor. $S$ is the grandmother of $T$ and is a housewife. There is one doctor,one contractor,one nurse,one housewife,and two students in the family. Which of the following are two married couples?

$P$ is the brother of $Q$. $M$ is the sister of $Q$. $T$ is the brother of $P$. How is $Q$ related to $T$?

$R$ is the daughter of $Q$. $M$ is the sister of $B$,who is the son of $Q$. How is $M$ related to $R$?

$A \div B$ means $A$ is the father of $B$,$A - B$ means $A$ is the wife of $B$,$A \times B$ means $A$ is the brother of $B$,$A + B$ means $A$ is the daughter of $B$.
If $P \times R \div Q$,which of the following is true?

$P \times Q$ means $P$ is the sister of $Q$; $P + Q$ means $P$ is the father of $Q$; $P - Q$ means $P$ is the mother of $Q$. Which of the following means $S$ is the aunt of $T$?