单选题 Too many teacher-directed activities cannot be expected to effectively ______ children in learning because of the rigid structure.

单选题 My ______ reaction to the news was relief, but as I thought more about it I began to feel angry.

单选题 Make sure the label is firmly ______ to the parcel before you mail it.

单选题 Professor Smith translated not only from the French but also, ______, from the Polish.

单选题 My boyfriend bought me dinner to ______ being late the day before.

单选题 ______, it was the wrong time to open a new data processing center in this city.

单选题 To use the machine, first ______ the correct coins, then select the drink you want and press the button.

单选题 A full understanding of mathematics is sufficient to explain a wide variety of natural ______.

单选题 Food chemists will ______ the health food on sale to see if it really does give the benefits claimed.