躯干后伸主动肌是（）
A.竖脊肌
B.半脊肌
C.多裂肌
D.腰方肌
E.背阔肌
参考答案：A, D
就划线部分提问。
1. It's Tuesday today.
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2. It's rainy today.
3. January first is New Year's Day.
4. Teachers' Day is September tenth.
物流对生产系统会产生哪些影响？
