Radium salts，which have been found to ______ in bones，give rise to bone cancer.

I have had my bike     , and I'm going to have somebody       my radio tomorrow.

His son __________ the old man with all the food and the money he needed.

When asked about the secret about staying young, he said that a balanced diet      with exercise was the recipe for a healthy life.

_____ his accent , he is from the south of China.