function insertSpaces($str) {
		$result = '';
		$length = mb_strlen($str, 'UTF-8');
		$i = 0;
		$k=0;
		while ($i < $length) {
			// 获取当前字符
			$char = mb_substr($str, $i, 1, 'UTF-8');
			if($i+1<$length){
				$char_next = mb_substr($str, $i+1, 1, 'UTF-8');
			}else{
				$char_next =" ";
			}
			if($char!=" "){
				$k++;
			}
			if($char!=" "&&$char_next==" "){
				// var_dump($k);
				if($k==2){
					$result=$result."  ".$char;
				}else{
					$result=$result.$char;
				}
				$k=0;
			}else{
				$result=$result.$char;
			}
			$i++;
		}
	
		return $result;
	}