90. I invited Joe and Linda to dinner, but ______ of them came.
| A．neither | B．either | C．none | D．Both |
Without proper lessons, you could _________a lot of bad habits when playing the piano.
| A．set up | B．catch up | C．pick up | D．keep up |
The college has developed an on-line system ________students can choose their own professors.
| A．where | B．when | C．that | D．which |
As a doctor , it’s against my ______ to accept gifts from patients.
| A．emotions | B．principles | C．regulations | D．opinions |
In communication, a smile is usually ______ strong sign of a friendly and ______ open attitude.
| A．the, / | B．a, an | C．a, / | D．the, an |
The Wangs are considering ______ to Huangshan for a trip at five tomorrow morning.
| A．to move off | B．moving | C．moving off | D．movement |