_____entering the classroom, remember to take your seat and turn off your cell phone.
| A．At | B．From | C．Upon | D．As |
all kinds of difficulties，the workers have made rapid progress in the construction of
the World Expo 2010 Shanghai．
| A．With | B．For | C．Under | D．Beyond |
—Bob! How’s your project? I heard you started it last Friday，right?
—Oh！Ifor it．But I haven’t decided when to do it．
| A．have prepared | B．had prepared |
| C．have been preparing | D．was preparing |
a diary every day and you’ll improve your writing．
| A．Keeping | B．To keep | C．Keep | D．If you keep |
If we had taken such effective measures much earlier, the riverso seriously now.
| A．is not polluted | B．would not be polluted |
| C．had not been polluted | D．would not have been polluted |
Thousands of Haitians cheered as the Chinese medical team arrived，many of ______even cried with joy.
| A．those | B．them | C．whom | D．who |