Questão 721972

READ TEXT II AND ANSWER QUESTIONS 14 TO 20:

TEXT II

THE CEREALS

Cereals are the staff of life for most of mankind.

Even our milk and our meat derive largely from them.

They are grasses nurtured and bred by man so that their

grain is large and nourishing. Except in parts of the

5 tropics where such roots as tapioca and yams are the

staple carbohydrate, and in wet cold places where the

potato plugs the gap, wheat, barley, oats, rye, rice,

maize and sorghum are what keeps us all alive and

kicking.

The cereals have all been bred from wild grasses,

and bred so far away from their parent stocks that they

are now distinct species. In fact it is sometimes difficult

to guess which wild grass a particular cereal is derived

from, and, in some cases, maize for example, the wild

15 species is now probably extinct.

(from Seymour, John. The Complete Book of Self-Sufficiency,London: Faber & Faber, 1980: 56)

The word sometimes in "it is sometimes difficult..." (l.12) can be replaced by: