then — choose the word that has the same consonant sound(s) as the one represented by the letter(s) underlined

The question is incomplete: the word with the underlined letter(s) did not come through, so I can't be sure which sound you're matching. The only clue is the word "then" at the end, which was probably the target word, with "th" underlined.

Step 1: Analyze the question This is a consonant-sound question (phonetics). You compare the underlined sound in the given word with the sounds in the options.

Step 2: Explain the concept The letters "th" can make two different sounds:

• Voiced /ð/, as in then, this, smooth, mother. The vocal cords vibrate. Put a finger on your throat and you will feel it.
• Voiceless /θ/, as in thaw, thin, wealthy, bath. There is only air, with no vibration.

Step 3: Work through the options (assuming "then" with /ð/)

• A. thaw has /θ/ (voiceless), so it does not match.
• B. smooth has /ð/ at the end (voiced, /smuːð/), so it matches.
• C. den has /d/, which is close but not the same sound.
• D. wealthy has /θ/ (voiceless, /ˈwelθi/), so it does not match.

Step 4: Answer Assuming the underlined sound is the "th" in then, the answer is B. smooth.

If the underlined sound in your original question was different, send me the full question and I'll recheck it.

Exam tip: To tell the two "th" sounds apart, say the word and feel your throat. If it vibrates, it's /ð/ (then, smooth, with). If it doesn't, it's /θ/ (thaw, wealthy, think). Words like the, this, that, those, them are all voiced.