pi-bonds are not seen in            `

In ${\text{CH}}_4$ and ${\text{H}}_2\text{O}$ there is only ${\text{sp}}^3$ hybridisation has been taking place in their central atoms at carbon and oxygen. So, as a result those molecules do not form pi – bonds or multiple bonds or in ${\text{CH}}_4$ and ${\text{H}}_2\text{O}$ the bonded atoms do not form double bonds so the contains only sigma bond and no pi bond.