[Haskell-beginners] ghci reports "The last statement in a 'do' construct must be an expression" error

Hi Heres my code snippet. It reports that my error is in line 9 right after the main definition. All functions that i call work under normal circumstances. Thanks module Benchmark where import ReadCSV import Operators import Data.Time.Clock (diffUTCTime, getCurrentTime) main = do xs <- readCSV "dataconvert/lineitem.tbl" '|' start <- getCurrentTime let pnp = projection [5] xs let snp = selection (\x -> (x!!0) > (Int 17000)) pnp end <- getCurrentTime putStrLn $ show (end `diffUTCTime` start) start2 <- getCurrentTime let pp = pProjection [5] xs let sp = pSelection (\x -> (x!!0) > (Int 17000)) pp end2 <- getCurrentTime putStrLn $ show (end2 `diffUTCTime` start2) return xs