血红素合成的限速酶是（）
A.ALA脱水酶
B.ALA合酶
C.尿卟啉原Ⅰ合成酶
D.血红素合成酶
E.尿卟啉原Ⅲ合成酶
参考答案：B
Now Yiwu Commodity City is famous ______ the world _____ its varieties of goods and low prices with high quality.
A．in;as
B．throughout; for
C．for; as
D．through; for
牙痛宜选（）。
A.肩井
B.至阳
C.合谷
D.颊车
E.内庭
