Charles Wortmann at the University of Nebraska-Lincoln says a one-time tillage may be used to correct a problem like aggressive weeds.

VOA: special.2010.09.28

Dentists say children should have their first dental visit at least by the time they are one year old.

VOA: special.2009.03.11

For a time he was one of only three doctors,and the only surgeon, at a huge hospital in Kinshasa.

VOA: special.2009.02.23

At the time,more than one hundred ninety countries agreed to reduce or halt biodiversity losses by twenty ten.

VOA: special.2010.05.25

They are the amount a person drinks on average and heavy drinking at one time, called "binge drinking."

VOA: special.2009.09.08

Marie Curie was one of the few women at the time who became famous as a scientist.

VOA: special.2009.05.13

In two thousand nine,at the age of ninety, he put on his Indians uniform one more time.

VOA: special.2011.01.09

She became one of the few black people at the time wealthy enough to give huge amounts of money to help people and organizations.

VOA: special.2010.03.28

Guides tell visitors that Lincoln lived at the house for one-fourth of his time as president.

VOA: special.2010.05.10

One expert said she was not warm and friendly like white, male singers at the time.

VOA: special.2010.05.23

At the same time,courts have ruled against any publicly supported celebrations of one religion over another.

VOA: special.2009.12.24

At one time in the past, my brother had been in love with this woman.

VOA: special.2009.07.19

Mark Johnson made the songs by recording one part of the song at a time.

VOA: special.2009.07.31

"Actually,there were a lot of Chinese going back to the People's Republic of China at that time, ninety-thousand in one year from Fukien Province alone.

VOA: special.2011.06.10