On this verse see 9.4. A different word is used for ground in these two verses, but they are synonyms (the word used in 9.4 is a more frequently used word).
Quoted with permission from Newman, Barclay M. and Nida, Eugene A. A Handbook on The Acts of the Apostles. (UBS Handbook Series). New York: UBS, 1972. For this and other handbooks for translators see here .