根據(jù)句意和漢語注釋，寫出單詞的正確形式。

1. Like many famous scientists, Li Siguang _________ (致力于) himself to the study of science.

2. _________ (醫(yī)療的) workers are badly needed in those earthquake-hit areas.

3. I don’t think the watch gives you good ________ (價值) for your money.

4. The tourists had no __________ （選擇）but to wait for the next train.

5. How are you going to ___ (證明) that it is very difficult for giant pandas to survive in the wild?