| 1. | He must have been doing experiment in the laboratory 他一定是在实验室里做实验。 |
| 2. | We cannot be too careful in doing experiments 我们做实验无论怎样小心也不会过分。 |
| 3. | In 1928 , he was doing experiments with bacteria 在1928年时,他正在进行细菌的实验。 |
| 4. | The teacher advised us to do experiments more carefully 老师建议我们要更细心地做实验。 |
| 5. | We cannot be too careful in doing experiments 我们做实验时越仔细越好。 |
| 6. | You can ' t be too careful in doing experiments 你做实验要特别小心。 |
| 7. | We ' ve been doing experiments 24 hours without a break 我们的实验已连续不断地进行了二十四小时。 |
| 8. | They did experiment after experiment and finally succeeded 他们做了一个又一个实验,最后成功了。 |
| 9. | Doing experiments is a good way to find out answers to questions 做实验是找到问题的答案的好方法。 |
| 10. | They did experiments year after year 他们年复一年地作实验 |