The thief broke in, trying to open the safe, but ___________.
| A．in no way | B．in vain | C．without effect | D．at a loss |
—What do you think I should wear for such a formal press conference?
—Dress _______ you like.
| A．how | B．what | C．whatever | D．however |
Radium salts，which have been found to ______ in bones，give rise to bone cancer.
| A．pile up | B．build up | C．keep up | D．pull up |
Our teacher insisted that the key words worth paying attention _______ before class.
| A．be underlined | B．being underlined |
| C．to be underlined | D．to being underlined |
With some technical problems to be solved, it may be a while _______ the system is put into use.
| A．when | B．after | C．since | D．before |
That is the only way we can imagine _______ the overuse of water in students’ bathrooms.
| A．reducing | B．to reduce | C．reduced | D．reduce |