22. 已知双曲线C:x2a−y2=1(a>0)C:\frac{{x}^{2}}{a}-{y}^{2}=1(a>0)C:ax2−y2=1(a>0)的一条渐近线为x+ay=0x+ay=0x+ay=0,则双曲线CCC的焦距为((( )))