In Hangzhou Mr. Black was so struck ____the beauty of nature that he stayed ____another night.A. at; on B. with; at C. for; in D. by; for 答案:D。“be struck by”意为“被……迷住/打动”,stay for the night表示“留下来过夜”。关于使用杠杆时用力,下列说法正确的是 [ ]
A.用动力臂长的杠杆省力
B.用阻力臂长的杠杆费力
C.用动力臂小于阻力臂的杠杆,省力
D.用阻力臂大于动力臂的杠杆,费力