Ielts speaking--how to improve your bandscore

What are some peculiar features of English sounds?
Certain sounds change when they are paired with another sound. One obvious
example is /s/. This can be pronounced in two different ways: /s/ and /z/.
It is pronounced /z/ when se comes after a vowel, just like the case of lose, use,
and cause.

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When s is preceded by a voiced sound, it is read as /z/. These are the sounds that
create a vibration in your vocal cords as you produce them. Like /r/, /g/, /d/, /b/,
/th/ (then), /v/, /l/, /z/, and /j/. Take for example eggs, beds, and dollars.
For the past tense of the regular verbs with infinitive forms that end in voiceless
sounds like /p/, /k/, /s/, /ch/, /sh/, /f/, /x/, /h/, ed is pronounced as /t/. Examples
are asked, baked, brushed, cooked, cracked, and crashed.
For infinitive verbs that end in voiced consonant sounds like /l/, /v/, /n/, /m/, /r/,
/b/, /g/, /w/, /y/, and /z/ and vowels, the ed in the past form is read as /d/.
Examples are the following:
agreed
allowed
answered
appeared
arrived
believe
belonged
burned
called
For verbs whose base forms end in /t/ or /d/, the ed is pronounced as id, such as
in wanted or decided.
Activity A