two-stage injector

例句：

1. 1. Thistwo-stage injector is designedto deliver drugs more precisely than a single-stage one.
   这种双阶段注射器设计用来比单阶段注射器更精确地输送药物。
2. 2. The new two-stage injector has been shown tobe more effective in treating chronic pain.
   新推出的双阶段注射器在治疗慢性疼痛方面显示出更高的效率。
3. 3. Thepatient was given the two-stage injector forpain relief, but it did notwork as expected.
   患者被给予双阶段注射器以缓解疼痛，但效果并不如预期。