Which adjective is not a correct alternative to “invaluable” (line 3)?

Text for the questions from 38 to 50.

Sound Advice for Language Learners

1 A recent issue of a language learning magazine has

consulted a number of experts in the field of second

language acquisition. Their advice may prove invaluable for

4 those considering a language course. Ask yourself some

basic questions, they suggest. Did you enjoy studying

languages at school, for example? Can you really afford the

7 time to learn a language?

First and foremost, you have to be realistic in your

goals. If you fail to set achievable aims you are likely to give

10 up. Besides, it is worth knowing that the most expensive

courses are not necessarily the best. You should also bear in

mind that the quicker you learn a language the more quickly

13 you forget it. Sue Miller, a French teacher, attempted to

teach herself German by enrolling on a crash course.

Already fluent in three languages, her chances of making

16 progress were high. Two years on she hardly remembers

anything. “I should have chosen a regular course in order to

have more time for practice and consolidation.”

19 Sue’s comment is certainly a good piece of advice.

Internet: <www.flo‐joe.uk> (adapted).