A:格里菲思实验
B:赫尔希、蔡斯实验
C:艾弗里实验
D:烟草花叶病毒侵染烟草实验
Name
Kate Green
Age
14
Birthday
____20th
Food
For breakfast:two eggs and some____.
Subjects
For lunch:rice and carrots
Telephone number
For dinner:____and salad
如图是用木棒撬石块的示意图,请在图中用小黑点标出支点,用符号O表示,并画 出动力F的力臂.