喷气纱由（）和包缠纤维两部分组成。
参考答案：纱芯
用所给动词的适当形式填空。
1. Li Ming _____________ (live) in China.
2. Li Ming _____________ (arrive) in Canada.
3. He wants _____________ (learn) English.
4. _____________ (do) you have a good trip?
5. _____________ (be) this your suitcase?
6. _____________ (be) these your shoes?
颈部以______为界分为颈前外侧部和颈后部。
