  Given two (hereditary) complete cotorsion pairs
$(\mathcal{X}_1,\mathcal{Y}_1)$ and $(\mathcal{X}_2,\mathcal{Y}_2)$ in an exact
category with $\mathcal{X}_1\subseteq \mathcal{Y}_2$, we prove that $\left({\rm
Smd}\langle \mathcal{X}_1,\mathcal{X}_2 \rangle,\mathcal{Y}_1\cap
\mathcal{Y}_2\right)$ is also a (hereditary) complete cotorsion pair, where
${\rm Smd}\langle \mathcal{X}_1,\mathcal{X}_2 \rangle$ is the class of direct
summands of extension of $\mathcal{X}_1$ and $\mathcal{X}_2$. As an
application, we construct complete cotorsion pairs, such as
$(^\perp\mathcal{GI}^{\leqslant n},\mathcal{GI}^{\leqslant n})$, where
$\mathcal{GI}^{\leqslant n}$ is the class of modules of Gorenstein injective
dimension at most $n$. And we also characterize the left orthogonal class of
exact complexes of injective modules and the classes of modules with finite
Gorenstein projective, Gorenstein flat, and PGF dimensions.
