Had electronic computers not been invented, many problems of space flight ______.
举一反三
- If computers ______, many problems on space flight could not have been solved. A: had not been invented B: are not invented C: were not invented D: have not invented
- All flight ____ because of the snowstorm, many passengers could do nothing but stay at the airport. A: had been cancelled B: were cancelled C: having been cancelled D: have been cancelled
- Electronic computers, which have many advantages, can not carry out creative work and replace man.
- When I was (at) the grocery store, I (realized) that the prices of (many items)(had been() risen). A: at B: realized C: many items D: had been risen
- John was late for the business meeting because his flight had been delayed by coronavirus.