■ “把针头从注射器上拿下来”可以说：detach the needle from the syringe。
把针头扎进某人的手臂
stick the needle into someone's arm
A：I felt a sudden pain when the nurse stuck the needle into my arm.
护士把针头扎进我手臂的那一刻，我突然感到一阵疼痛。
B：It's normal. The pain usually disappears soon.
这是正常的。疼痛通常很快就会消失。
stick /st?k/ v. 扎；刺；戳
normal /?n??ml/ adj. 正常的
disappear /?d?s??p??(r)/ v. 消失；失踪；遗失
把针头从某人的血管里拔出来
withdraw the needle from someone's blood vessel
A：The moment the nurse withdrew the needle from his blood vessel, he heaved a sigh of relief.