Question

select all the pairs of adjacent angles.
∠bca and ∠dca
∠efh and ∠efc
∠dcf and ∠bcf
∠bca and ∠bcf

Explanation:

Step1: Recall adjacent - angle definition

Adjacent angles share a common vertex and a common side, and no interior points in common.

Step2: Check $\angle BCA$ and $\angle DCA$

They share vertex $C$ and side $CA$, so they are adjacent.

Step3: Check $\angle EFH$ and $\angle EFC$

They share vertex $F$ and side $EF$, so they are adjacent.

Step4: Check $\angle DCF$ and $\angle BCF$

They share vertex $C$ and side $CF$, so they are adjacent.

Step5: Check $\angle BCA$ and $\angle BCF$

They share vertex $C$ and side $BC$, so they are adjacent.

Answer:

$\angle BCA$ and $\angle DCA$, $\angle EFH$ and $\angle EFC$, $\angle DCF$ and $\angle BCF$, $\angle BCA$ and $\angle BCF$