It is safe to eat chicken that ________fully, but most people still dare not do that because of the H7N9 bird flu .
She always watches her son ________ the road every morning, or she will feel worried.
Finally, people found computers ________.
They still can’t decide ________ with our difficulties in learning math.
Everybody tells us we can’t pass the exam ________ we study hard.
– How do you learn English, Tony? – I usually practice English ________ chatting with my American friends.