．Only when Tom fully recovered___________back to work.

Occasions are quite rare ____ I have thetime to spend a day with my kids

What a dangerous scene! A car has missed the boy playing on the roadside________ only an inch.[ ]

Can I use the telephone on the table，sir–Under no circumstances _________ to use the telephone in the office for personal affairs．

If we cannot __________ the subject of astronomy，we won’t get the job opportunities on space stations.[ ]