Experts do not know for sure about his mother,Caterina.

VOA: special.2010.09.15

No one seems to know for sure.

VOA: special.2010.06.27

While analysts say no one knows for sure how many jobs the stimulus has created, President Obama says he's under no illusions that one program alone can solve the nation's economic problems.

VOA: standard.2010.06.18

"When you can't say for sure whether all the women in the advance provision group actually used the medication, then you're kind of looking at population level effect of a strategy, not the individual effect of a medication."

VOA: standard.2010.03.22

"For sure the military will not only clear and secure the area, but ensure unless and until the area is taken over completely by the civil administration, and the writ of the government is restored and peace and normalcy return to the area, the military will remain in the area,".

VOA: standard.2009.05.07

The scientist says this mission has been planned for many years, but he is not sure when it will happen.

VOA: special.2010.05.25

When he was sure she was dead, Murlock had sense enough to remember that the dead must be prepared for burial.

VOA: special.2009.10.31

Experts are not sure whether this tribe placed bodies in caves as part of burial ceremonies or for other reasons.

VOA: special.2010.11.10

They are also advised not to give anti-reflux medicines for hoarseness unless they are sure patients need them.

VOA: special.2009.09.02

Michael J.Fox says he is sure that a cure for Parkinson's disease will be found in the future.

VOA: special.2009.04.07

They felt sure of success. For now,enough leaders of the Southern Alliance were willing to support the idea.

VOA: special.2010.06.10

Treasury Secretary Chase was for the plan only if Lincoln was sure it would not mean war.

VOA: special.2009.08.06

For instance,even native speakers are often not sure when to use "lie" and when to use "lay."

VOA: special.2010.02.11

Be sure to join us again next week for THIS IS AMERICA in VOA Special English.

VOA: special.2009.05.04