1. With experience, and with improved apparatus,
    根据经验和改进了的仪器，

2. The past forty years saw great success in the control of spreading diseases and great strides toward achieving "health for all by the year 2000" (a major WHO goal) through improved basic health care, food, cleanliness, and immunization(免疫)
    在过去的40年中，通过改善基本医疗保健、食品、卫生和免疫等项目，人类在控制流行病方面取得了巨大的进步，并且朝着实现"2000年人人享受健康"（世界卫生组织的一项主要目标）迈出了一大步。

3. No doubt about it, solitude is improved by being voluntary.
    毫无疑问，如果自愿独处，则感觉要好得多。

4. Some students have limited writing abilities which need to be improved before or as part of the online experience.
    网上学习之前或作为网上学习的一部分，许多写作能力有限的学生必须提高书面表达能力。

5. One group was exercised by running inside an automatic wheel, a second group improved their skills in a complicated obstacle course, and a third group was inactive.
    第一组在自动轮中跑动，第二组通过一种复杂的越障训练来提高技能，第三组则不做任何运动。

6. That the blood poison is, so to speak, a newer product from an improved formula.
    而溶血性毒液，打个比方说，是根据改良配方生产的一种较新的产品。