您要查找的是不是：
- We have three periods of chemistry a week. 我们一星期三节化学课。
- The scientist probed into the secrets of chemistry. 这位科学家探索了化学的种种奥秘。
- Chemistry was her favourite subject at school. 她上学时最喜欢化学。
- I can't trace that letter you sent me. 我找不到你寄给我的那封信。
- No one can cope with him in Chemistry. 在化学方面，谁也比不上他。
- He spoke without a trace of emotion. 他说话时毫不动感情。
- I am not good at organic chemistry. 我的有机化学学得不好。
- Did the police find any trace of the murderer? 警方找到凶手的行踪了吗？
- We will do a Chemistry experiment this Friday. 这个周五我们要做化学试验。
- They failed to find any trace of the runaways. 他们未能找到逃跑者的任何踪迹。
- There was barely a trace of salt in the soup. 汤里简直一点盐也没有放。
- The post office tried to trace the lost letter. 邮局设法查出那封丢失的信。
- The kids are learning to trace the letter. 孩子们学描字母。
- He always spoke with a trace of sarcasm. 他说话总带着一丝讽刺。
- He is an authority in the region of chemistry. 他是化学界的权威。
- I have only a rudimentary grasp of chemistry. 我只掌握了化学的初步知识。
- I have lost my interest in chemistry. 我对化学已不感兴趣。
- He was still devoted to the study of chemistry. 他仍专心致力於化学研究。
- The powerhouse was trace out accurately later on a large scale map. 后来发电站被精确地描画在大比例地图上。
