plunge into
US /plʌndʒ ˈɪntuː/
UK /plʌndʒ ˈɪntuː/

1.
投入, 陷入
to suddenly start doing something or become involved in something, often without careful thought
:
•
He decided to plunge into the new business venture without hesitation.
他决定毫不犹豫地投入新的商业冒险。
•
After graduation, she will plunge into a demanding career.
毕业后,她将投身于一份要求很高的职业。