这篇文章的过渡衔接词，使文章条理清晰，衔接紧密，值得借鉴。
A Food Poisoning Accident
Last month, I witnessed a food poisoning accident happening to my classmates. At that time the situation was really very dangerous and urgent. Though finally they got out of danger, this accident is still vivid in my mind.
That day was Julie’s birthday, one of my classmates. In order to celebrate it, her roommates bought a big birthday cake for her from a supermarket nearby. They shared the cake happily. However, after a while, all of them felt abdominal pain, nausea and dizziness. Two of them even cannot stand up because of great pain. We rushed to send them to the hospital. It turned out that the cake they ate had expired its guarantee period. Futunately, due to timely treatment, they all recovered very soon.
]However, this accident leaves me a deep ponder. I think it is very urgent to take effective measures to improve food safety. Firstly, the government should strengthen supervision and administration on food safety. More importantly, to those who immoral businessmen, more strict punishment should be given. Besides, we consumers should be more careful in buying food. Only in this way can we make sure that no same accident happens.
