7. (10th "Hope Cup" Invitational Competition Question) If the graph of the function $y=\log _{\frac{1}{2}}|x+a|$ does not pass through the second quadrant, then the range of values for $a$ is ( ).
A. $(0,+\infty)$
B. $[1,+\infty]$
C. $(-\infty, 0)$
D. $(-\infty,-1]$
7. D. Reason: The graph of the function $y=\log _{\frac{1}{2}}|x+a|$ is a logarithmic function graph symmetric about the line $x=-a$. When the graph on the left side of the line $x=-a$ does not pass through the second quadrant, the graph on the right side of the line $x=-a$ will certainly not pass through the second quadrant. For this, it is only necessary that $a \leqslant$ -1.