您要查找的是不是：
- Some stars are invisible to the naked eye. 有些星体肉眼是看不见的。
- He remains invisible when out of spirits. 闷闷不乐时，他不露面。
- Germs are invisible to the naked eye. 细菌用肉眼看不见。
- The gun can fire invisible rays. 这枪能发出看不见的射线。
- The mends were almost invisible. 修补过的地方几乎看不出来。
- That comet is invisible to the unaided eye. 那颗彗星只用肉眼是看不到的。
- The differences are almost invisible. 这些差别简直难以辨认。
- The office has been humming with activity. 办公室一直忙着搞活动。
- She was invisible in the dusk of the room. 她在昏暗的房间里别人看不到她。
- The threat of war has depressed business activity. 战争的威胁使经济萧条。
- There has been a lot of activity in the town today. 今天市中心相当热闹。
- The town was humming with activity. 该市镇生气勃勃，呈现一片热闹的景象。
- Stamp collecting is my favorite activity. 集邮是我最喜爱的消遣。
- The store was a scene of great activity. 这家商店顾客盈门。
- He once engaged in anti-government activity. 他一度从事反政府的活动。
- Invis fade time down to 5 seconds. 隐形减至5秒。
- The office is humming with activity. 办公室里一片忙碌。
- A center of interest or activity. 中心兴趣或活动的中心
- Showing no optical activity in polarized light. 无旋光的极化光下无光学反应的
- An increase, as in movement or business activity. 进步，改进，改善运动或商业活动的进步或兴隆
