Some instructions
How do I write the instruction: "Write the address on the envelope."

How do I ask these questions? Are the oranges the sweetest fruit?
What day (of the week) is it today?

What different ways are there to say "Talk with your friend". ?
How do I say "There is no-one here."

To say 5 bananas, is this correct? 五梭香蕉

Question

Some instructions
How do I write the instruction:  "Write the address on the envelope."

How do I ask these questions? Are the oranges the sweetest fruit?
What day (of the week) is it today?

What different ways are there to say "Talk with your friend". ?
How do I say "There is no-one here."

To say 5 bananas, is this correct? 五梭香蕉

Answer

Write the address on the envelope.→ 信封要寫上地址 
Are the oranges the sweetest fruit?→ 柳丁是最甜的水果嗎？ 
What day (of the week) is it today?→ 今天是星期幾？or 今天是禮拜幾？ 
Talk with your friend.→ 跟你朋友說 or 跟你朋友講 or 跟你朋友談談(it deepens your context) 
There is no-one here.→ 這裡沒人 or 沒人or 沒有人 or 沒人啊 (it deepens your context) 
五梭香蕉→ 五根香蕉

Answer

Cantonese will say "五梭香蕉". But others will prefer to use  "把， 串，盘...”  as the classifer for several bananas connected together.  As " 只， 条， 根” ，we can use it to describe individual bananas.

Answer

Write the address on the envelope.→ 信封要寫上地址

Are the oranges the sweetest fruit?→ 柳丁是最甜的水果嗎？
What day (of the week) is it today?→ 今天是星期幾？or 今天是禮拜幾？

Talk with your friend.→ 跟你朋友說 or 跟你朋友講 or 跟你朋友談談(it deepens your context)

There is no-one here.→ 這裡沒人 or 沒人or 沒有人 or 沒人啊 (it deepens your context)

五梭香蕉→ 五根香蕉