A：went; was occurring
B：went; occurred
C：was going; occurred
D：was going; had occurred
下列对细菌的描述正确的是（ ）
达尔文认为：自然界中的生物在生存竞争中，____生存，其它的将被淘汰的过程，称为____．
写出下列字的笔画顺序
军：____
念：____
He ________having been frightened.
