生态系统的稳定性是由于生态系统具有_________________________________。
一定的自我调节能力
根据句意及首字母提示,完成单词拼写。
1. Mary comes from A ___.
2. My grandmother likes taking p __.
3. This hamburger is very d __.
4. My grandpa was a teacher. But now he is r _.
5. I want to buy a d for learning English.
“皇帝”成为我国最高封建统治者的称谓,首创于()
A.秦王嬴政
B.汉高祖刘邦
C.唐太宗李世民
D.宋太祖朱元璋