In the following English vocabulary question, select the one-word substitute for the expression “to have saliva dripping copiously from the mouth”.

Introduction / Context:
One-word substitution questions test whether you can replace a long phrase with a single, precise English word. In this question, you must choose the word that correctly represents the action “to have saliva dripping copiously from the mouth”. Such vocabulary is often used to describe animals, babies, or sometimes people in an informal or humorous way, so it is important to know the exact term.

Given Data / Assumptions:

• Phrase given: “Have saliva dripping copiously from the mouth”.
• We need a verb that directly expresses this action.
• The correct word should relate specifically to saliva and the mouth.
• Only one option should truly match the phrase.

Concept / Approach:
The key idea in the phrase is the excessive flow of saliva from the mouth. The standard English verb for this is “slobber”. Other words like “cascade”, “inundate”, “sluice”, and “trickle” describe the movement of liquids such as water, but they are not specifically linked to saliva or the mouth. A good strategy is to focus on the subject (mouth and saliva) rather than just any flowing liquid.

Step-by-Step Solution:
Step 1: Identify the core meaning: saliva is coming out of the mouth in noticeable quantity. Step 2: Recall common verbs related to saliva, such as “drool”, “dribble”, and “slobber”. Step 3: Examine the options and see which one naturally collocates with saliva and mouth. Step 4: “Slobber” is used exactly to mean to let saliva run from the mouth, usually in a messy way. Step 5: Confirm that other options do not usually describe saliva from a mouth and therefore do not fit the phrase accurately.

Verification / Alternative check:
You can test each option in a sample sentence: “The dog began to ____ when it saw the food.” Only “slobber” sounds natural and correct, while “cascade”, “inundate”, “sluice”, or “trickle” sound odd or unnatural in everyday English. This confirms that “slobber” is the appropriate one-word substitute.

Why Other Options Are Wrong:
“Cascade” means to fall or pour down like a waterfall. It is not specifically linked to saliva or the mouth.
“Inundate” means to flood or overwhelm, usually with water, work, or information, not saliva from a mouth.
“Sluice” refers to letting water out through a channel or gate. It is a technical term and does not describe drooling.
“Trickle” means to flow slowly in small drops, but it does not specifically refer to saliva and is not the accepted one-word substitute for this phrase.

Common Pitfalls:
A common mistake is to choose a word only because it describes some kind of flow, without checking whether it is used with saliva. Another pitfall is ignoring the emotional tone: “slobber” suggests messiness and lack of control, which matches the idea of saliva dripping copiously. To avoid errors in such questions, always check common usage and typical combinations of words in your mind or through practice sentences.

Final Answer:
The correct one-word substitute is “slobber”.