Importing a CSV file

I have been trying to import a csv file to r. but I get the same message everytime. the message is

Error in file(file, "rt") : cannot open the connection
In addition: Warning message:
In file(file, "rt") :
  cannot open file 'Users:/sezginozcan/Downloads/beer.data.csv': No such file or directory

I use mac.
I tried this command also
a<-read.table("clipboard",sep=”\t”,row.names=1,header=T)
Error: unexpected input in "a<-read.table("clipboard",sep=‚"

I will appreciate if you help me before I get crazy.
thank you