What does the underlined word “arduous” in Paragraph 5 mean?

(单选题)After completing and signing it, please return the form to u (单选题)The old man, ______ for twenty years, is on the way back to (单选题)The washing machine does not function anymore and I need to (单选题)No matter how careful you are, there will always be a degree (单选题)Young people nowadays could not imagine what difficulty thei (单选题)Basketball is a good game for children. It ______ great exer (单选题)The manager ______ the workers how to improve the program si (单选题)The letters for the manager ______ on his desk but he didn’t (单选题)The dog seems very quiet now, but he still ______ go by. (单选题)We’d visited the village without advance notice and selected