difficult to eradicate difficult to erase difficult to escape difficult to establish difficult to estimate difficult to evaluate difficult to examine difficult to execute difficult to exercise difficult to expect difficult to explain difficult to exploit difficult to express difficult to extract difficult to face difficult to feel difficult to fight difficult to fill difficult to finance difficult to find difficult to fit difficult to fix difficult to focus difficult to follow difficult to foresee difficult to forget difficult to forge difficult to formulate difficult to form difficult to fulfill difficult to fulfil difficult to gain difficult to gather difficult to get difficult to give difficult to go difficult to grasp difficult to grow difficult to guarantee difficult to guess difficult to handle difficult to have difficult to heal difficult to hear difficult to heat difficult to help difficult to hide difficult to hold difficult to identify difficult to ignite difficult to ignore difficult to imagine difficult to implement difficult to impose difficult to improve difficult to include difficult to incorporate difficult to increase difficult to influence difficult to insert difficult to install difficult to integrate difficult to interpret difficult to introduce difficult to investigate difficult to judge difficult to justify difficult to keep difficult to kill difficult to know difficult to learn difficult to leave difficult to lift difficult to link difficult to live difficult to locate difficult to look difficult to lose difficult to machine difficult to maintain difficult to make difficult to manage difficult to manipulate difficult to manufacture difficult to master difficult to match difficult to measure difficult to meet difficult to miss difficult to modify difficult to monitor difficult to motivate difficult to move difficult to name difficult to navigate difficult to negotiate difficult to notice difficult to observe difficult to obtain difficult to operate difficult to organise difficult to organize difficult to overcome difficult to overstate difficult to pass difficult to pay difficult to penetrate difficult to perceive difficult to perform difficult to persuade difficult to pick difficult to pinpoint difficult to place difficult to plan difficult to play difficult to please difficult to predict difficult to prepare difficult to present difficult to preserve difficult to prevent difficult to procure difficult to produce difficult to promote difficult to pronounce difficult to prosecute difficult to protect difficult to prove difficult to provide difficult to pull difficult to pursue difficult to push difficult to put difficult to quantify difficult to raise difficult to reach difficult to read difficult to realise difficult to realize difficult to receive difficult to recognise difficult to recognize difficult to recommend difficult to reconcile difficult to reconstruct difficult to recover difficult to recycle difficult to reduce difficult to refuse difficult to regain difficult to regulate difficult to relax difficult to remain difficult to remember difficult to remove difficult to repair difficult to replace difficult to replicate difficult to reproduce difficult to resist difficult to resolve difficult to respond difficult to restore difficult to retain difficult to return difficult to reverse difficult to run difficult to satisfy difficult to save difficult to say difficult to secure difficult to see difficult to select difficult to sell difficult to send difficult to show difficult to sit difficult to sleep difficult to solve difficult to speak difficult to start difficult to stay difficult to stop difficult to store difficult to study difficult to summarise difficult to summarize difficult to surprise difficult to survive difficult to sustain difficult to swallow difficult to tackle difficult to take difficult to talk difficult to teach difficult to tell difficult to think difficult to tolerate difficult to trace difficult to track