原因状语从句because等用法 — 英语填空题
题目
从方框中选词填空，每词限用一次：because / since / because of
Lily never gives up when things get hard. She stayed calm during the exam ___ she had prepared for it carefully. ___ everyone knew she had worked hard for months, no one was surprised at her success. Her confidence comes mainly ___ her daily practice.