’It helps to have a very sharp knife when ~ ‘

Hi, Deepcosmos,

@deepcosmos posted:

We can use a similar pattern with “it + verb + (object) + clause” using a verb other than ‘be’:

• It helps to have a very sharp knife when you prepare fish.
• It didn't surprise me when Pete left the company.

Which is, do you think, the extraposed subject between “to have a very sharp” and “when you prepare fish” for the underlined sentence above? I’m so confused.

Notice that "object" is between parentheses in that pattern, which means that it may or may not be present in the structure. What the book stresses there is that a verb other than "be" can be introduced by "it."

In the first sentence, there is no object and the subject is "to have a very sharp knife":
- To have a very sharp knife helps when you prepare fish.

In the second sentence, the object is "me" but I don't think "when Pete left the company" is the extraposed subject. I interpret that "it" as situational, not as preparatory or anticipatory. This is not grammatical:
* When Pete left the company surprised me.

The book provides another example with an object:

- It worried me that she drove so fast.

In this sentence, "me" is the object and "that she drove so fast" is the extraposed subject.

@Gustavo, Co-Moderator posted:

Notice that "object" is between parentheses in that pattern, which means that it may or may not be present in the structure. What the book stresses there is that a verb other than "be" can be introduced by "it."

In the first sentence, there is no object and the subject is "to have a very sharp knife":
- To have a very sharp knife helps when you prepare fish.

Hi, Gustavo, appreciate your reply.

By the way, can the infinitive clause in the pattern "It helps to do" with dummy it + without object be an extraposed subject, since I think "to do" is the verbial complement for the catenative verb - "help"?

Of course, I'm quite sure the 'to infinitive' clause is the exptraposed subject as in "It helps <me> to buy bread daily.", which has the object.

@deepcosmos posted:

By the way, can the infinitive clause in the pattern "It helps to do" with dummy it + without object be an extraposed subject, since I think "to do" is the verbial complement for the catenative verb - "help"?

I think you are confusing the verb patterns with "help" with the main verb "help" meaning "be of help." Notice the difference:

- It (The sharp knife) helps (the butcher) (to) cut the fish. (Here "help (sb) (to) do sth" is a verb pattern.)

- It helps to have a sharp knife. (Here "help" means "is of help," and "to have a sharp knife" is the extraposed subject: To have a sharp knife helps / is of help.)

@Gustavo, Co-Moderator posted:

I think you are confusing the verb patterns with "help" with the main verb "help" meaning "be of help." Notice the difference:

- It (The sharp knife) helps (the butcher) (to) cut the fish. (Here "help (sb) (to) do sth" is a verb pattern.)

- It helps to have a sharp knife. (Here "help" means "is of help," and "to have a sharp knife" is the extraposed subject: To have a sharp knife helps / is of help.)

Hi, Gustavo, you did pull me out of a trap with a nice explanation in which you replace "help" with "be of help".

With your explanation only now do I feel the "help" as a catenative verb would be applied only to the case when the subject is a personal pronoun (including "it") as in "Could you help (to) wash up, please?"

By the way, haven't you ever seen "when clause" act as an extraposed subject for dummy 'it'? If ever, please let me know an example.

@deepcosmos posted:

By the way, haven't you ever seen "when clause" act as an extraposed subject for dummy 'it'? If ever, please let me know an example.

For a "when"-clause to act as an extraposed subject, it needs to be a nominal relative, not an adverbial of time. Notice how this "wh"-clause you had quoted from "Advanced Grammar in Use" is nominal:

• It is clear why Don decided to leave Spain = The reason why Don decided to leave Spain is clear.

@deepcosmos posted:

• It helps to have a very sharp knife when you prepare fish.

In this sentence that you proposed in your opening post, "when you prepare fish" is an adverbial clause of time specifying when it is useful to have a sharp knife. "It" anticipates the infinitival, not the "when"-clause. For a "when"-clause to be anticipated by "it," the clause needs to be nominal, for example:

• It is unclear when Don will return to Spain = The time when Don will return to Spain is unclear.

@Gustavo, Co-Moderator posted:

• It is clear why Don decided to leave Spain = The reason why Don decided to leave Spain is clear.
• It is unclear when Don will return to Spain = The time when Don will return to Spain is unclear.

Hi, Gustavo, much appreciate your additional explanation addressing "a nominal relative" 'why' and 'when'.  I guess the two relatives above might be also interpreted as "interrogative" 'why' and 'when' consisting an indirect question. What do you think about its possibilty?

Yes, we can consider them to be embedded questions:

• We know why Don decided to leave Spain.
• We don't know when Don will return to Spain.