wǒ xūyào huí qù, ránhòu dǎ diànhuà gěi wǒ de māma.

Use 给 to mark the recipient of a call: it functions like “to” in English. With 打电话, Chinese uses:

• 给+人+打电话 (e.g., 给我妈妈打电话)
• 打电话给+人 (e.g., 打电话给我妈妈)

Using 对 with 打电话 is not idiomatic. You say 对他说 (“say to him”), but not 对他打电话.

回 is the verb “to return,” and 去/来 adds direction relative to the speaker:

• 回去 = go back (away from where the speaker is)
• 回来 = come back (to where the speaker is) So 回去 is correct if the “back” destination is not where the speaker currently is.

Not necessarily. 回去 can stand alone if context is clear. If you want to be explicit, add a place:

• 回家 (go back home)
• 回学校
• 回公司 You can also combine with direction: 回家去 (common in speech), but plain 回家 is most typical.

• 然后 = “and then” (narrates sequence; neutral).
• 再 = “then/next” (often plan-like or instruction-like; commonly used with 先).
• Serial-verb without a connector is also natural: 回去打电话 = “go back and call.”

All three are fine; pick based on tone:

• Neutral narration: 回去，然后…
• Step-by-step plan: 先回去，再打电话
• Concise: 回去打电话

For completed events, put 了 after each verb phrase:

• 我回去了，然后给我妈打了电话。 If narrating one completed sequence, many also say:
• 我回去以后给我妈打了电话。 Use 过 for past experience (ever done), not a specific one-time event:
• 我给我妈打过电话。 (I have called my mom before.)

Yes. You can say:

• 给我妈打一下电话 (perfectly fine)
• More colloquial: 给我妈打个电话 (using a measure word sounds even more natural) Avoid placing 一下 after the whole phrase; it belongs right after the verb: 打一下.

打电话 is the fixed collocation: 打 covers “dial/make” in this context. Alternatives:

• 拨电话/拨打电话 (dial/make a call) — more formal or used in instructions/announcements. Colloquial 打给他 is shorthand for 打电话给他 (common, especially in Taiwan). Avoid forms like 打给他电话.

No. 打电话 is a verb-object set phrase and doesn’t work well with 把 in that way. Say:

• 给我妈妈打电话
• 打电话给我妈妈 Using 把电话打给… is unnatural.

No. Standard Chinese writing does not use spaces between words. The segmentation shown is for learners. A natural written line would be:

• 我需要回去，然后打电话给我妈妈。