Here's the passage again with a few of the words explained in modern English.
A cook they hadde with hem for the nones (occasion)
To boille the chiknes with the marybones (marrowbones) ,
And poudre-marchant (spices) tart and galyngale (ginger-like root) .
Wel koude he knowe a draughte of londoun ale.
He koude rooste, and sethe (boil), and broille, and frye,
Maken mortreux (stews), and wel bake a pye.
But greet harm was it, as it thoughte me,
That on his shyne a mormal (open sore) hadde he.
For blankmanger, that made he with the beste.
A shipman was ther, wonynge (living) fer by weste (in the West);
For aught I woot (for all I know), he was of Dertemouthe (from Dartmouth).
He rood upon a rounce (pack horse) , as he kouthe (could),
In a gowne of faldyng (wool) to the knee.
A daggere hangynge on a laas (cord) hadde he
Aboute his nekke, under his arm adoun.
The hoote somer hadde maad his hewe (colour) al broun;
And certeinly he was a good felawe.
Ful many a draughte of wyn had he ydrawe (drawn)
Fro Burdeux (Bordeaux) -ward, whil that the chapmen sleep.
Of nyce (careful) conscience took he no keep (notice).
If that he faught, and hadde the hyer hond,
By water he sente hem hoom (them home) to every lond.
But of his craft to rekene wel his tydes,
His stremes, and his daungers hym bisides,
His herberwe (harbourage) , and his moone, his lodemenage (piloting),
Ther nas (was not) noon swich from hulle to cartage (Carthage – North Africa).
Hardy he was and wys to undertake;
With many a tempest hadde his berd been shake.
He knew alle the havenes (harbours), as they were,
Fro Gootlond to the Cape of Fynystere,
And every cryke (creek) in Britaigne (Brittany) and in Spayne.
His barge ycleped was (was called) the Maudelayne.
Now look at the exercises on the next page.