Complete the sentence by putting the verb in brackets into the passive (Present Simple, Past Simple, Present Perfect, Future Simple or Modal). Changes (make)...to the prototype and the design (modify)...
Now giant anchors (sink)... into the bottom of the sea.

To complete the sentence, we need to put the verb in brackets into the passive form.

1. Changes (make)... to the prototype and the design (modify)...
In this case, we need to use the Simple Past passive form of the verbs "make" and "modify". The sentence would be: Changes were made to the prototype and the design was modified.

2. Now giant anchors (sink)... into the bottom of the sea.
Here, we need to use the Present Simple passive form of the verb "sink". The sentence would be: Now, giant anchors are sunk into the bottom of the sea.

Let me explain each step in detail:

1. Changes (make)... to the prototype and the design (modify)...
To put the verb "make" into the passive form, we use the verb "be" in the appropriate tense (in this case, Simple Past) followed by the past participle of the main verb. The past participle of "make" is "made".
Therefore, the passive form of "make" in the Simple Past tense is "were made".

To put the verb "modify" into the passive form, we follow the same rule. The past participle of "modify" is "modified".
Therefore, the passive form of "modify" in the Simple Past tense is "was modified".

Combining the passive forms of both verbs, we get: Changes were made to the prototype and the design was modified.

2. Now giant anchors (sink)... into the bottom of the sea.
To put the verb "sink" into the passive form, we use the verb "be" in the appropriate tense (in this case, Present Simple) followed by the past participle of the main verb. The past participle of "sink" is also "sunk".
Therefore, the passive form of "sink" in the Present Simple tense is "are sunk".

The complete sentence would be: Now, giant anchors are sunk into the bottom of the sea.

By using the passive voice, we emphasize the action being performed on the subject (prototype, design, and giant anchors) rather than the subject performing the action. This sentence structure is commonly used when the focus is on the result or the process rather than the agent performing the action.