The security regulations of Manchester Airport are not changed from time to time.
举一反三
- The motives for writing vary from person to person and from time to time.( )
- D detox(数字排毒) is time spent away from computers and other digital devices from time to time.
- They used to be at ______ with each other and had quarrels from time to time.
- 中国大学MOOC: The data will need _______ from time to time.
- On the table ................ (is, are) a pile of books which he consults from time to time.