The store had to a number of clerks because sales were down.
| A．lay out | B．lay off | C．lay aside | D．lay down |
Many approaches have been _______ to control the spread of H7N9 Bird Flu.
| A．adapted | B．employed | C．negotiated | D．accessed |
Roger had just walked into his office and that was when he was told that his plan had finally been approved. Which of the following can be instead of the underlined(划线的) part to make the sentence better.
| A．and then they told him | B．when it was learned by him |
| C．and then he learned | D．when he learned |
The sunspot came into its active stage, __________ that happens once every eleven years.
| A．one | B．it | C．the one | D．what |
It’s already 10’clock. I wonder how it ____ that she was two hours late on such a short trip.
| A．came over | B．came out | C．came about | D．came up |
Many strange new means of transport have been developed in our century, the strangest of _____ being perhaps the hovercraft(气垫船).
| A．which | B．them | C．that | D．it |