新手求助

ADOQuery4.SQL.Add('Insert into Libray_Borrow ([Level], Btime, Who, WhoID, Status, IDBook, Stime_date, Stime_time )' + 'values ('+ QuotedStr(Level)+','+QuotedStr(Btime)+','+QuotedStr(Who)+','+QuotedStr(WhoID)+','+QuotedStr(Status)+','+QuotedStr(IDBook)+','+QuotedStr(Stime_date)+','+QuotedStr(Stime_time)+')+');
运行的时候，就是倒数三行有错误提示：Incompatible :'String' and 'Integer'
求高手指点