The verbal group: tenses

Exercise 9: Answer
Aquatic hyphomycetes in freshwater habitats can be distinguished into the Ingoldian and the
aeroquatic groups (Webster & Descals, 1980). The Ingoldian hyphomycetes
are known
to
grow profusely on well-­‐decayed leaves and twigs in running streams and lakes. Their spores
were
first
observed
on stream surface scum by Ingold (1942). Since then, over 150 species

have

been described
but mostly from temperate countries. Few such fungi
have been
reported
from the tropics. This paper
presents
some observations made on a survey for
Ingoldian hyphomycetes in the local freshwaters.
(Tan and Lim, 1980:36)

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Basic English Grammar Module: Unit 2B. Independent Learning Resources
© Learning Centre University of Sydney. This Unit may be copied for individual student use.
27
1.
The
present passive
is used to introduce the general topic to be
discussed.
2.
The
simple past
and the
present perfect
are used to discuss the previous
research.
3.
The
simple present
is used to identify the aim of the paper.