Attention, please! And keep ________ when I am taking a photograph of you.
| A．still | B．calm | C．quiet | D．silent |
_____ he is very busy, he spends at least two hours every day surfing the Internet in order to find out the latest development in science and technology.
| A．Even though | B．When | C．Unless | D．Whether |
Several weeks had gone by _____ the head of the gallery realized the painting was missing.
| A．after | B．before | C．since | D．that |
The airline has a booklet _____ will tell you most of the important information to Europe.
| A．in which | B．about which | C．/ | D．that |
Students can easily fall behind in their studies ____ they don’t manage their spare time carefully.
| A．though | B．if | C．since | D．until |
He warmly congratulated them on _____ they had achieved in science and technology.
| A．that | B．where | C．what | D．which |