We know such people are not ___.
| A．to rely on | B．to be relied upon | C．to be relied | D．to rely upon |
—How many practical plans has your deskmate made this week?
—. All have turned out disappointing.
| A．None | B．Nothing | C．Nobody | D．No |
The best times to visit Shangri-la are spring and autumn ____ the temperature is at its mildest.
| A．when | B．where | C．that | D．which |
Scientists study ____ human brains work to make computers.
| A．when | B．how | C．that | D．whether |
______ in the school campus in spring, we will always noitce a colorful display of flowers.
| A．Walk | B．Having walked | C．Being walking | D．Walking |
It’s great that all the visitors who _______ on the island were saved.
| A．trapped | B．have been trapped | C．had trapped | D．had been trapped |