Use a or an before each of the following words. 1 __ pair of jeans 2 __ ....... train 3 __ apple tree 4 __ ..oxygen pump . 5 __ ... bag

## Step 1<br />The first step in this problem is to understand the rule of using 'a' and 'an'. 'A' is used before words that begin with a consonant sound, while 'an' is used before words that begin with a vowel sound.<br /><br />## Step 2<br />The word 'pair' begins with a consonant sound /p/, so we use 'a' before it.<br /><br />## Step 3<br />The word 'train' begins with a consonant sound /t/, so we use 'a' before it.<br /><br />## Step 4<br />The word 'apple' begins with a consonant sound /æ/, so we use 'an' before it.<br /><br />## Step 5<br />The word 'oxygen' begins with a vowel sound /o/, so we use 'an' before it.<br /><br />## Step 6<br />The word 'bag' begins with a consonant sound /b/, so we use 'a' before it.