A：蛋白质
B：DNA
C：荚膜
D：RNA
我国四大工业基地中，以重工业为主的是
下列关于生态系统中物质循环和能量流动的叙述，正确的是（ ）
鸟宿池边树，____。《题李凝幽居》贾岛
给下列句子选择合适的答语。
① How do you like this chess? ____ A. It's$50.
② How much is this sweater?____ B. Yes How much is it?
③ The socks are $50. ____ C. It's very pretty.
④ Can l help you? ____ D. They're too expensive.
