In the 1950s in the USA, most families had just one phone at home, and wireless phones _______ yet.
| A． |
haven't invented |
B． |
haven't been invented |
| C． |
hadn't invented |
D． |
hadn't been invented |
Generally, students’inner motivation with high expectations from others_________ essential to their development.
| A．is | B．are |
| C．was | D．were |
Professor Smith, along with his assistants, on the project day and night to meet the deadline.
| A．work | B．working |
| C．is working | D．are working |
A number of methods been used, but the number of animals still small in the forest.
| A．have; is | B．has; is |
| C．have; are | D．has; are |
A great number of visitors __________ attracted to my hometown, and the number of foreigners there _______ quite large.
| A．are; are | B．is; is |
| C．is; are | D．are; is |
----The singer together with her band_______ invited to the concert. Did you enjoy that party?
----No, hardly_____ when they sang their top hit Oh, My Baby.
| A．was, I had left | B．were, I have gone |
| C．was, had I left | D．were, did I leave |