A new technique ____ out, the yields increased by 20% .
| A．having working | B．having been working |
| C．has worked | D．had been worked |
. When Jack reached the station the train ______ for ten minutes.
| A．had gone | B．had set off | C．had been away | D．had left |
After ______ seemed a long time, Mr. Li stood up and broke the silence.
| A．what | B．that | C．it | D．which |
Allow others the space to voice their opinions, ______ they are different from yours.
| A．as though | B．as if | C．unless | D．even though |
Is the occasion near ______ we can practice our talents?
| A．when | B．which | C．that | D．what |
Though he was disabled, he was never satisfied ______ he did the best of a normal child.
| A．after | B．until | C．unless | D．when |