Terjemahan
Many Vietnamese students learning Chinese find that some Chinese words sound very much like Vietnamese, for example “注意” (attention), “准备” (prepare) and “经济” (economy). This is because Vietnamese has a large number of words borrowed from Chinese. This helps Vietnamese students memorise words quickly, but it can also cause problems: some words don't mean exactly the same thing in the two languages, and if you guess only from the sound, you may use them wrongly. So teachers advise looking such words up in a dictionary and checking the example sentences.
Penerangan
Step 1: skim the four options first so you know what to look for (memorising speed, guessing from sound, meanings of Sino-Vietnamese words, the teachers' advice). Step 2: match them with the text: “如果只靠发音去猜,就可能用错” (if you guess only from the sound you may use it wrongly) is paraphrased as “根据发音猜词义不一定可靠” (guessing meaning from sound is not always reliable), which is the answer. Step 3: rule out the others: the text says students memorise words “比较快” (quite fast), not slowly; meanings are “并不完全相同” (not exactly the same), so “都一样” is wrong; and the teachers recommend “看看例句”, the opposite of D. Tip: in this part the right option is almost always a paraphrase, while wrong options change one key word (快 → 慢, 不完全相同 → 都一样).