Question

1.We saw an aeroplane (add a subordinate clause to expand the sentence)
2.(a) ignore (b)imagine (add suffix and preffix)

Answer 1

Please, find below the correct answers.

The sentence, we saw an aeroplane, consists of a single independent clause. In order to increase the length of the sentence one needs to add a subordinate clause preceded by a conjunction. An example is given below.  

1. We saw an aeroplane until that took off and disappeared into the clouds.

A word part placed at the end of a word is termed to be Suffix whereas a word part placed before a word is called Prefix. The examples of prefixes and suffixes are given below.

2.  a. Ignore

    i. Ignorable

    ii. Unignorable

    b. Imagine

    i. Imaginable

Answer 2

Subordinate clause is added to a statement with the help of a conjunction. Therefore, the possible answer could be:

"We saw an aeroplane when the sky was clear."

Prefix refers to attaching the letters "before" a given word. This causes several changes such as conversion of form, change in meaning, etc. However, suffix is defined as the letters placed "after" an expression. This again changes the form or meaning of the operated word.

Moreover, below is the answer of part (2).

(a) Ignore- Unignore (prefix: "un"); Ignorer (suffix: "r" converts the word into noun)

(b) Imagine- Reimagine (prefix: "re"); Imagined (suffix: "d" changes the form).