In a recent experiment to test their theory the researchers had a helicopter descend into the fog ab

Vanloon

Senior Member
Hindi
Creativity Exercise

Researchers believe that if warm dry air above the fog could somehow be driven down into the humid blanket of god, the droplets would evaporate, thus clearing the air. In a recent experiment to test their theory the researchers had a helicopter descend into the fog above barely visible Smith Mountain Airport near Roanoke, Virginia.

At the second sentence, I would like know the structure of it.

In a recent experiment to test their theory the researchers had a helicopter descend into the fog above barely visible Smith Mountain Airport near Roanoke, Virginia.

1. 'In a recent experiment to test their theory' is prepositional phrase? If then, I think after 'theory' this sentence should have comma.
like 'In a recent experiment to test their theory, the researchers had a helicopter descend into the fog above barely visible Smith Mountain Airport near Roanoke, Virginia.'
Am I right?

2. I think Main subject is 'the researchers' and main verb is 'had'. Am I right?


3. 'descend' is verb? If then, Why there are two verbs here?

Thanks in advance!!
 
  • PaulQ

    Senior Member
    UK
    English - England
    {[In a recent] [experiment that was designed to test their theory]} [the researchers had a helicopter descend] {[into the fog] that (i.e. the fog) was above barely visible Smith Mountain Airport near Roanoke, Virginia)

    There is only one verb in the main clause (in italics), and it is in the causative voice: "had descend"

    The causative form of the verb and indicates that the subject arranged for something to happen to himself or someone/something else.

    I will have my house painted on Tuesday = My house will be painted on Tuesday [by painters]
    I got my hair cut yesterday = My hair was cut yesterday [by the barber.]
     
    Last edited:

    Vanloon

    Senior Member
    Hindi
    Thanks for your quick reply. Question 2, 3 were solved but question 1 is still vague for me. After prepositional phrase(in a recent experiment...theory), why there is no 'comma' here?

    Thanks!
     

    PaulQ

    Senior Member
    UK
    English - England
    "Wrong" is a little harsh - I would say that it is better with a comma. If you are answering a question in an exam, you should add the comma.
     
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