te is a careful and experienced engineer, so heis often to finish somechallenging tasks

In my class, boys don’t love morning _______, but they like doing ______ in the playground.

Remember to ________ a good state of mind even if you should fail plenty of times．

Betty will ring me up as soon as she ________ in Shanghai.

Not until all the fish die in the river ____ how serious the pollution was. [ ]