Jane _____ these families of chimps for many years and helped people understand how much they behave like humans.
| A．had studied | B．studied | C．studies | D．has studied |
After we boarded the boat, it went on down the river, stopping ____ to take people in.
| A．more or less | B．now and then | C．sooner or later | D．up and down |
. The year 2003 ____ a wild spread of SARS, a disease people knew little about at that time.
| A．accompanied | B．followed | C．saw | D．caused |
The company turned a deaf ear to the workers’ _____ about their pay and working conditions.
| A．complaints | B．application | C．supplies | D．consequences |
Today’s world is changing rapidly, making _____ necessary for us to continue learning otherwise we can’t keep up with the time.
| A．us | B．it | C．this | D．one |
. ---- It’s a secret _____ you and me.
| A．beyond | B．within | C．between | D．among |