胸外心脏按压时，有效按压深度为（）
A.1～2cm
B.2～3cm
C.3～4cm
D.4～5cm
E.5～6cm
参考答案：D
The Golden Gate Bridge is a famous landmark in San Francisco. The USA. Which of the following words
is created in the same way as the word landmark?[ ]
A. unpleasant
B. useless
C. summertime
D. surprising
侧滑块的有效导向长度应小于滑块导滑槽的宽度
