I've been working hard on this grammar topic but I still haven't fully figured it out.

1-) These are machines that take room air and extract the nitrogen, producing greater than 90% pure oxygen.

The word "producing" in this sentence is reduced relative clause (refer to "machines" ) or cause-result ( adverbial ) ?

2-) The drug disrupted the mechanism in the body, causing a heart attack.
The drug disrupts the mechanism in the body, causing a heart attack.

Is it necessary to have the past tense in such sentences ? Because only past tense examples are given in any book. For example :

The engineer fixed the problem, earning a promotion or She slipped on the ice, breaking her ankle.

3-) Our bodies can sweat, losing heat by evaporation.

Can this sentence be thought of in two ways? For example :

Our bodies can sweat and this ( our bodies can sweat ) causes loss of heat by evaporation

Our bodies can sweat and (our bodies ) lose heat by evaporation

I would be very grateful if you could help with examples and enlighten me. Thank you.

  • These are three good questions, but unfortunately we only allow one question here at a time. If you want answers to all these questions, I encourage you to ask three different questions. When you've reduced edited this question down to just one question, we'll be happy to reopen it.
    – gotube
    Commented Nov 27, 2022 at 18:11

2 Answers 2


The first can't work as reduced relative clauses (the clause would modify "nitrogen", and that doesn't make sense)

In the second case there is the potential for ambiguity, (the drug could cause a heart attack by disrupting a mechanism in the body. Or the drug could disrupt a mechanism in the body that causes heart attacks, and so the drug prevents heart attacks) The placement of the comma means that only the first reading is possible, ie the drug caused the heart attack.

These participle phrases can be used in both past and present tense sentences (with the usual meaning of the tense)

In the last example, while it might be formally ambiguous, the purpose of sweat (not sweet) is to cool the body. So this is the only possible understanding. The sweat takes the heat away. You can cool a body, but you can't cool the process of sweating.


[1] These are machines that take room air and extract the nitrogen, [producing greater than 90% pure oxygen].

[2] The drug disrupted the mechanism in the body, [causing a heart attack].

[3] Our bodies can sweat, [losing heat by evaporation].

The bracketed elements are all adjuncts, i.e. modifiers in clause structure.

In [2] it's a result adjunct: it expresses the result of the drug disrupting the mechanism in the body.

I'm not entirely sure what semantic type the adjuncts in [1] and [3] belong to, though there's a sense in which you could talk of purpose.

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