一、单词拼写。
结合语境，根据汉语提示用单词的适当形式填空。
1．She talked for about twenty minutes without even ________(停顿) for breath.
2．They had planned to take a picnic on the ________(海岸) of Lake Havel.
3．Make sure that all gas fires and central heating boilers are serviced ________(每年)．
