help the people in the snowstorm in the south made him worried．
A. Not known how to
B. Unknown what to do to
C. His knowing not how to
D. His not knowing how to
网友回答
A. Not known how to
B. Unknown what to do to
C. His knowing not how to
(答案→)D. His not knowing how to
解析：可联系答.案.网客服索取。