About one fourth of the families in the city have private cars and this number _____ to double in five years.
| A．is expecting | B．has expected | C．is expected | D．will expect |
John Logie Baird constructed the first color TV in 1928, but it was not until 1938 ______ the first color TV programme was broadcast.
| A．when | B．what | C．which | D．that |
Since his retirement from teaching music in 2001, Mr. Smith ______ a good deal of time painting as an artist.
| A．spent | B．has spent | C．had spent | D．spends |
Lawrence Craven, a doctor from the US, introduced the idea in 1953 _______ aspirin has the potential to reduce the risk of heart attacks.
| A．that | B．when | C．which | D．why |
Keeping on doing good deeds brings us peace of mind, ________ is important for our happiness.
| A．which | B．that | C．what | D．it |
_______ I have never thought of getting a job in such a big company, I’ll have a go at it.
| A．Since | B．Unless | C．Once | D．While |