1. Merry Christmas is the correct way to express "圣诞快乐" in English. It is a common holiday greeting used in English-speaking countries to wish others a joyful and festive Christmas season.

2. In terms of pronunciation, Merry Christmas can be read as /ˈmɛri ˈkrɪsməs/. The first word "Merry" is pronounced with a short "e" sound, while the second word "Christmas" is pronounced with a short "i" sound. The stress falls on the first syllable of each word.

3. Christmas is an important holiday celebrated worldwide on December 25th. It is a time of joy, love, and giving. Christians celebrate the birth of Jesus Christ on this day. Families and friends come together to exchange gifts, decorate Christmas trees, and enjoy special meals.

4. Many traditions and customs are associated with Christmas, such as singing Christmas carols, hanging stockings, and preparing delicious Christmas feasts. Santa Claus, also known as Father Christmas, is a beloved figure who brings gifts to children on Christmas Eve.

5. Christmas is a time for spreading happiness and goodwill. It is a time to be grateful for the blessings in our lives and to show love and kindness to others. Many people also attend church services and participate in acts of charity during this festive season.

6. In conclusion, Merry Christmas is the correct greeting for expressing "圣诞快乐" in English. It is pronounced as /ˈmɛri ˈkrɪsməs/ and is associated with a joyous and festive holiday celebrated on December 25th. Christmas is a time for love, giving, and spreading happiness. It is a special occasion that brings people together and reminds us of the true meaning of the holiday season.