At the railway station,the mother waved goodbye to her son until the train was .
Scientists say it may be one year or so ________ it is possible to test the new medicine on human patients.
It is reported that 70% of people in China are ________ about the food security situation after so many accidents.
You have made a few mistakes in your composition but _______ you have done well.
The big fire destroyed a 28-story high-rise apartment building , _______58 people with 56 missing and more than 120 others ______.
----People should stop using their cars and start using public transport. ---- ________. The roads are too crowded as they are.