9000101001

Determine whether two lines $p$ and $q$ are identical, parallel, intersecting or skew. $$\begin{array}{rlrl}p:x& =1+t,& & \\ y& =2-t,& & \\ z& =1-t;t\in \mathbb{R}& & \end{array}$$ $$\begin{array}{rlrl}q:x& =2s,& & \\ y& =-1,& & \\ z& =2-2s;s\in \mathbb{R}& & \end{array}$$