Some tourists’ visiting Tian’anmen Square during the holiday left a ________ of litter everywhere they went.
| A．trail | B．dot | C．chain | D．track |
When and where to go for the on-salary holiday _____ yet.
| A．are not decided | B．have not been decided |
| C．is not being decided | D．has not been decided |
The water will be polluted unless some measures _____.
| A．will be taken | B．are being taken | C．are taken | D．were taken |
His way of speaking suggested that he ____ very angry.
| A．should be | B．be | C．is | D．was |
Pine trees, of which there are almost one hundred _____, are found throughout the North Temperate Zone.
| A．species | B．samples | C．specimens | D．Standards |
The salmon dish was _______, wasn’t it?
| A．success | B．the success | C．a success | D．successes |