Butterflies ________ a sweet liquid produced by flowers, which bees and other insects collect.
| A．carry on | B．feed on |
| C．put on | D．focus on |
____ either he or I to attend the mass meeting this evening.
| A．is | B．am | C．are | D．be |
Either he or I ____ to attend the mass meeting this evening.
| A．is | B．am | C．are | D．be |
To play basketball and to go swimming ___ useful for character-training.
| A．was | B．is | C．are | D．were |
Early to bed and early to rise ____ a good habit.
| A．are | B．is | C．were | D．was |
Both rice and wheat ____ grown in that country.
| A．is | B．are | C．was | D．has |